In-phase corporate-feed circuit and array antenna apparatus
As a layout requirement imposed on an in-phase corporate-feed circuit, there is provided only a layout requirement to equalize the electric length of a transmission line (4) between one of N T-branch units (6) which is m-th when counted from a start point of a path A, and another one of the T-branch units (6) which is (m+1)-th when counted from the start point of the path A, to that of a transmission line (8) between one of N T-branch units (10) which is m-th when counted from an end point of a path B, and another one of the T-branch units (10) which is (m+1)-th when counted from the end point of the path B. Therefore, the in-phase corporate-feed circuit can be formed in a space smaller than that in which its circuit configuration of tournament type is formed, and downsizing of the circuit size can be achieved.
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The present invention relates to an in-phase corporate-feed circuit that generates plural signals having equal phases from a single signal, and an array antenna apparatus in which the in-phase corporate-feed circuit is mounted.
BACKGROUND ARTAs an in-phase corporate-feed circuit that generates plural signals having equal phases from a single signal, an in-phase corporate-feed circuit having a circuit configuration of tournament type is disclosed in Patent Literature 1 listed below.
In this in-phase corporate-feed circuit, plural power dividers of Wilkinson type each of which is provided as a power divider that divides a single signal into two signals in phase are formed in a plane circuit.
Further, transmission lines that connect the plural power dividers in the shape of a binary tree are formed in the plane circuit.
An in-phase corporate-feed circuit can be used for an array antenna apparatus which is typified by a phased array antenna.
A phased array antenna is one in which plural element antennas are arranged, and can vary the transmission directions of electromagnetic waves which are transmission waves by changing the phases of signals to be outputted to the element antennas.
Typically, a transmitter is connected to each of the element antennas, and is equipped with a phase shifter that can vary the phase of a signal.
Therefore, in order to control the phase of an electromagnetic wave emitted from each of the element antennas, it is necessary to input a signal to the transmitter equipped with the phase shifter.
Because there are many cases in which the phase shifters mounted in the plural transmitters can control the phases of signals more easily when the phases of the signals inputted to the plural transmitters are equal, there is a case in which the in-phase corporate-feed circuit is configured to generate plural signals having equal phases from a single signal, and provide the signals in phase for the plural transmitters.
CITATION LIST Patent LiteraturePatent Literature 1: Japanese Patent Application Publication No. 2006-108741 (for example, see
Because the conventional in-phase corporate-feed circuit is formed as above, the conventional in-phase corporate-feed circuit needs to satisfy a layout requirement to arrange the plural power dividers in the shape of a binary tree, and a layout requirement to equalize all of the lengths of transmission lines which are the output lines of power dividers arranged at the same level of the binary tree. A problem is that in order for the conventional in-phase corporate-feed circuit to satisfy the two layout requirements, the in-phase corporate-feed circuit cannot be formed in a plane circuit unless a space spreading out greatly in two dimensions is ensured, and this results in upsizing of the circuit size.
Particularly, in a case in which the plural element antennas and the plural transmitters are arranged at unequal intervals, the symmetry of the arrangement of the element antennas is broken. Therefore, it is necessary to match the lengths of transmission lines which are the output lines of plural power dividers at the final stage connected to plural transmitters to that of the transmission line of the power divider at the final stage which is located at the longest distance to the corresponding transmitter. Therefore, it is necessary to bend and route the transmission lines of the other power dividers at the final stage which are located at shorter distances to the corresponding transmitters, as appropriate. For this reason, it is necessary to ensure a space which is larger than that in a case in which the plural transmitters are arranged at equal intervals.
The present invention is made in order to solve the above-mentioned problems, and it is therefore an object of the present invention to provide an in-phase corporate-feed circuit and an array antenna apparatus capable of easing a layout requirement and achieving downsizing of the circuit size.
Solution to ProblemAccording to the present invention, there is provided an in-phase corporate-feed circuit including: a signal generating circuit configured to divide a signal generated thereby; a first transmission line having an end connected to the signal generating circuit, and another end terminated; a second transmission line having an end connected to the signal generating circuit, and another end terminated; N first branch circuits where N is an integer equal to or greater than 2, each first branch circuit being configured to take, from the first transmission line, a part of one of signals obtained by the division in the signal generating circuit; N second branch circuits, each second branch circuit being configured to take, from the second transmission line, a part of another one of the signals after division by the signal generating circuit; and N phase adding circuits, each phase adding circuit being configured to add a phase of a signal taken by one of the N first branch circuits which is n-th when counted from the end of the first transmission line where n is a positive integer equal to or less than N, and a phase of a signal taken by one of the N second branch circuits which is n-th when counted from the other end of the second transmission line. An electric length of the first transmission line between one of the first branch circuits which is m-th when counted from the end of the first transmission line where m is a positive integer equal to or less than N−1, and another one of the first branch circuits which is (m+1)-th when counted from the end of the first transmission line, is equal to an electric length of the second transmission line between one of the second branch circuits which is m-th when counted from the other end of the second transmission line, and another one of the second branch circuits which is (m+1)-th when counted from the other end of the second transmission line.
Advantageous Effects of InventionAccording to the present invention, because as a layout requirement imposed on the in-phase corporate-feed circuit, there is provided only a requirement to equalize the electric length of the first transmission line between a first branch circuit which is m-th when counted from the end of the first transmission line, and another first branch circuit which is (m+1)-th when counted from the end of the first transmission line, to that of the second transmission line between a second branch circuit which is m-th when counted from the other end of the second transmission line, and another second branch circuit which is (m+1)-th when counted from the other end of the second transmission line, there is provided an advantage of being able to achieve downsizing of the circuit size.
Hereafter, in order to explain this invention in greater detail, the embodiments of the present invention will be described with reference to the accompanying drawings.
Embodiment 1In
A signal generating circuit 1 includes a signal generator 2 and a power divider 3.
The signal generator 2 is an oscillator that generates a signal. As this signal generator, for example, a quartz oscillator, a phase locked oscillator (PLO), or the like can be considered.
The power divider 3 has one input terminal and two output terminals, and, when a signal generated by the signal generator 2 is provided for the input terminal, divides the power of the signal into two parts and outputs signals in phase from the two output terminals.
As the configuration of the power divider 3, for example, a circuit configuration of resistance type or Wilkinson type is used.
A transmission line 4 is a first transmission line having an end connected to the power divider 3 of the signal generating circuit 1, and another end connected to a terminator 5. At points of the transmission line 4, T-branch units 6a, 6b, and 6c are inserted. A signal path extending from the power divider 3 to the terminator 5 is referred to as a path A. As the transmission line 4, for example, a coaxial cable, a waveguide, a microstrip line formed on a printed circuit board, or the like is used.
Hereafter, a transmission line between the power divider 3 and the T-branch unit 6a is denoted by 4a, a transmission line between the T-branch unit 6a and the T-branch unit 6b is denoted by 4b, and a transmission line between the T-branch unit 6b and the T-branch unit 6c is denoted by 4c. Thus, the transmission line 4 includes the transmission lines 4a, 4b, and 4c. It is desirable that all of the characteristic impedances of the transmission lines 4a, 4b, and 4c are equal.
The terminator 5 consists of, for example, a resistor or the like, and terminates the other end of the transmission line 4 in order to prevent an unnecessary reflection of a signal at the other end of the transmission line 4. As a result, because a signal outputted from the power divider 3 is terminated by the terminator 5, the signal is not reflected at the other end of the transmission line 4 and does not flow backward toward the power divider 3.
An input port IN of the T-branch unit 6a is connected to the transmission line 4a, an output port OUT of the T-branch unit 6a is connected to the transmission line 4b, and an output terminal 7a is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 6a is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 7a.
An input port IN of the T-branch unit 6b is connected to the transmission line 4b, an output port OUT of the T-branch unit 6b is connected to the transmission line 4c, and an output terminal 7b is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 6b is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 7b.
An input port IN of the T-branch unit 6c is connected to the transmission line 4c, an output port OUT of the T-branch unit 6c is connected to the terminator 5, and an output terminal 7c is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 6c is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 7c.
The T-branch units 6a, 6b, and 6c construct first branch circuits.
A transmission line 8 consists of, for example, a coaxial cable, a waveguide, a microstrip line formed on a printed circuit board, or the like. The transmission line 8 is a second transmission line having an end connected to the power divider 3 of the signal generating circuit 1, and another end connected to a terminator 9. At points of the transmission line 8, T-branch units 10a, 10b, and 10c are inserted. A signal path extending from the power divider 3 to the terminator 9 is referred to as a path B.
Hereafter, a transmission line between the power divider 3 and the T-branch unit 10a is denoted by 8a, a transmission line between the T-branch unit 10a and the T-branch unit 10b is denoted by 8b, and a transmission line between the T-branch unit 10b and the T-branch unit 10c is denoted by 8c. Thus, the transmission line 8 includes the transmission lines 8a, 8b, and 8c. It is desirable that all of the characteristic impedances of the transmission lines 8a, 8b, and 8c are equal.
The terminator 9 consists of, for example, a resistor or the like, and terminates the other end of the transmission line 8 in order to prevent an unnecessary reflection of a signal at the other end of the transmission line 8. As a result, because a signal outputted from the power divider 3 is terminated by the terminator 9, the signal is not reflected at the other end of the transmission line 8 and does not flow backward toward the power divider 3.
An input port IN of the T-branch unit 10a is connected to the transmission line 8a, an output port OUT of the T-branch unit 10a is connected to the transmission line 8b, and an output terminal 11a is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 10a is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 11a.
An input port IN of the T-branch unit 10b is connected to the transmission line 8b, an output port OUT of the T-branch unit 10b is connected to the transmission line 8c, and an output terminal 11b is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 10b is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 11b.
An input port IN of the T-branch unit 10c is connected to the transmission line 8c, an output port OUT of the T-branch unit 10c is connected to the terminator 9, and an output terminal 11c is connected to a line branching from a line connecting between the input port IN and the output port OUT. As a result, a signal inputted from the input port IN of the T-branch unit 10c is branched into signals, and the branch signals are outputted from the output port OUT and the output terminal 11c.
The T-branch units 10a, 10b, and 10c construct second branch circuits.
A phase adding circuit 12a includes a mixer 13a and a filter 15a.
The mixer 13a has an input terminal 14a-1 and an input terminal 14a-2, and, when a signal after branching by the T-branch unit 6a is inputted from the input terminal 14a-1 and a signal after branching by the T-branch unit 10c is inputted from the input terminal 14a-2, mixes the two signals inputted thereto and outputs a mixed signal to the filter 15a.
The filter 15a passes a component having a phase which is the sum of the phases of the two signals included in the mixed signal outputted from the mixer 13a. As a result, the component passing through the filter 15a and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16a.
A phase adding circuit 12b includes a mixer 13b and a filter 15b.
The mixer 13b has an input terminal 14b-1 and an input terminal 14b-2, and, when a signal after branching by the T-branch unit 6b is inputted from the input terminal 14b-1 and a signal after branching by the T-branch unit 10b is inputted from the input terminal 14b-2, mixes the two signals inputted thereto and outputs a mixed signal to the filter 15b.
The filter 15b passes a component having a phase which is the sum of the phases of the two signals included in the mixed signal outputted from the mixer 13b. As a result, the component passing through the filter 15b and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16b.
A phase adding circuit 12c includes a mixer 13c and a filter 15c.
The mixer 13c has an input terminal 14c-1 and an input terminal 14c-2, and, when a signal after branching by the T-branch unit 6c is inputted from the input terminal 14c-1 and a signal after branching by the T-branch unit 10a is inputted from the input terminal 14c-2, mixes the two signals inputted thereto and outputs a mixed signal to the filter 15c.
The filter 15c passes a component having a phase which is the sum of the phases of the two signals included in the mixed signal outputted from the mixer 13c. As a result, the component passing through the filter 15c and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16c.
In Embodiment 1, a circuit comprised of the two T-branch units 6a and 10c and the phase adding circuit 12a is referred to as a circuit element 17a, and a circuit comprised of the two T-branch units 6b and 10b and the phase adding circuit 12b is referred to as a circuit element 17b. Further, a circuit comprised of the two T-branch units 6c and 10a and the phase adding circuit 12c is referred to as a circuit element 17c.
Although in
In Embodiment 1, the angular frequency of a signal outputted from the signal generator 2 is ω, and it is assumed that, at a time t, the voltage of the signal outputted from the signal generator 2 is expressed by cos(ωt).
Further, it is assumed that the electric length of the transmission line 4a at the angular frequency ω is θ1, the electric length of the transmission line 4b at the angular frequency ω is θ2, and the electric length of the transmission line 4c at the angular frequency ω is θ3.
In addition, it is assumed that the electric length of the transmission line 8a at the angular frequency ω is θ4, the electric length of the transmission line 8b at the angular frequency ω is θ3, and the electric length of the transmission line 8c at the angular frequency ω is θ2
Therefore, the electric length θ2 of the transmission line 4b between the T-branch unit 6a which is first when counted from the end of the transmission line 4 connected to the power divider 3, i.e., from a start point of the path A, and the T-branch unit 6b which is second when counted from the start point of the path A, is equal to the electric length θ2 of the transmission line 8c between the T-branch unit 10c which is first when counted from the other end of the transmission line 8 connected to the terminator 9, i.e., from an end point of the path B, and the T-branch unit 10b which is second when counted from the end point of the path B.
Further, the electric length θ3 of the transmission line 4c between the T-branch unit 6b which is second when counted from the start point of the path A, and the T-branch unit 6c which is third when counted from the start point of the path A, is equal to the electric length θ3 of the transmission line 8b between the T-branch unit 10b which is second when counted from the end point of the path B, and the T-branch unit 10a which is third when counted from the end point of the path B.
Next, operations will be explained. In Embodiment 1, for the sake of simplicity, it is assumed that the transmission time required for a signal generated by the signal generator 2 to reach the power divider 3 can be neglected, and the signal is divided into signals in phase by the power divider 3, because the signal generator 2 and the power divider 3 are connected directly to each other, not via any transmission path. More specifically, it is assumed that the phase of a signal outputted from the power divider 3 to the transmission line 4 and the phase of a signal outputted from the power divider 3 to the transmission line 8 are not out of phase with each other.
It is further assumed that phase variations which are caused by the transmission of signals by the power divider 3, the T-branch units 6a to 6c and 10a to 10c, and the filters 15a to 15c can be neglected.
In addition, it is assumed that the T-branch unit 6c and the terminator 5 are connected directly to each other, not via any transmission path, the T-branch unit 10c and the terminator 9 are connected directly to each other, not via any transmission path, and the mixers 13a to 13c and the filters 15a to 15c are connected directly to each other, not via any transmission paths.
It is further assumed that the input impedances of the mixers 13a to 13c are high.
When the signal generator 2 generates a signal, the power divider 3 of the signal generating circuit 1 divides the power of the signal into two parts and outputs signals in phase to the transmission line 4 and the transmission line 8.
The signal outputted from the power divider 3 to the transmission line 4 passes through the T-branch units 6a to 6c and is terminated by the terminator 5.
Further, the signal outputted from the power divider 3 to the transmission line 8 passes through the T-branch units 10a to 10c and is terminated by the terminator 9.
At this time, when a signal is inputted from the input port IN, each of the T-branch units 6a to 6c inserted onto the transmission line 4 outputs a part of the signal to a corresponding one of the output terminals 7a to 7c because the branch line is disposed for the line connecting between the input port IN and the output port OUT.
Further, when a signal is inputted from the input port IN, each of the T-branch units 10a to 10c inserted onto the transmission line 8 outputs a part of the signal to a corresponding one of the output terminals 11a to 11c because the branch line is disposed for the line connecting between the input port IN and the output port OUT.
In the mixers 13a to 13c of the phase adding circuits 12a to 12c, the input terminals 14a-1 to 14c-1 are connected to the output terminals 7a to 7c, and the input terminals 14a-2 to 14c-2 are connected to the output terminals 11c to 11a.
However, because the input impedances of the mixers 13a to 13c are high, voltages appear at the output terminals 7a to 7c and 11c to 11a, but no currents flow toward the input terminal 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c.
The phases of signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c are shown by the following equation (1), and all of the phases of these signals differ from one another.
Output terminal 7a:ωt+θ1
Output terminal 7b:ωt+θ1+θ2
Output terminal 7c:ωt+θ1+θ2+θ3
Output terminal 11a:ωt+θ4
Output terminal 11b:ωt+θ4+θ3
Output terminal 11c:ωt+θ4+θ3+θ2 (1)
When the signal outputted from the output terminal 7a of the T-branch unit 6a is inputted to the input terminal 14a-1 of the mixer 13a and the signal outputted from the output terminal 11c of the T-branch unit 10c is inputted to the input terminal 14a-2 of the mixer 13a, the mixer 13a mixes the two signals inputted thereto and outputs a mixed signal to the filter 15a.
When the signal outputted from the output terminal 7b of the T-branch unit 6b is inputted to the input terminal 14b-1 of the mixer 13b and the signal outputted from the output terminal 11b of the T-branch unit 10b is inputted to the input terminal 14b-2 of the mixer 13b, the mixer 13b mixes the two signals inputted thereto and outputs a mixed signal to the filter 15b.
When the signal outputted from the output terminal 7c of the T-branch unit 6c is inputted to the input terminal 14c-1 of the mixer 13c and the signal outputted from the output terminal 11a of the T-branch unit 10a is inputted to the input terminal 14c-2 of the mixer 13c, the mixer 13c mixes the two signals inputted thereto and outputs a mixed signal to the filter 15c.
Each of the mixed signals outputted from the mixers 13a to 13c includes a component having a phase which is the sum of the phases of the two signals, a component having a phase which is the difference between the phases of the two signals, and higher-order mixed wave components.
When receiving the mixed signal from the mixer 13a, the filter 15a prevents the passage of the component having a phase which is the difference between the phases of the two signals and the higher-order mixed wave components, which are included in the mixed signal, and passes only the component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15a and having a phase which is the sum of the phases of the two signals is outputted from the output terminal 16a.
When receiving the mixed signal from the mixer 13b, the filter 15b prevents the passage of the component having a phase which is the difference between the phases of the two signals and the higher-order mixed wave components, which are included in the mixed signal, and passes only the component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15b and having a phase which is the sum of the phases of the two signals is outputted from the output terminal 16b.
When receiving the mixed signal from the mixer 13c, the filter 15c prevents the passage of the component having a phase which is the difference between the phases of the two signals and the higher-order mixed wave components, which are included in the mixed signal, and passes only the component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15c and having a phase which is the sum of the phases of the two signals is outputted from the output terminal 16c.
The phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are shown by the following equation (2).
Output terminal 16a:(ωt+θ1)+(ωt+θ4+θ3+θ2)=2 ωt+θ1+θ2+θ3+θ4
Output terminal 16b:(ωt+θ1+θ2)+(ωt+∝4+θ3)=2 ωt+θ1+θ2+θ3+θ4
Output terminal 16c:(ωt+θ1+θ2+θ3)+(ωt+θ4)=2 ωt+θ1+θ2+θ3+θ4 (2)
As is clear from the equation (2), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
Although in Embodiment 1 the example in which the in-phase corporate-feed circuit is equipped with the three circuit elements 17a, 17b, and 17c is shown, the present embodiment can also be applied even to a case in which the number of circuit elements mounted is two, or four or more.
Concretely, in a case in which the number of circuit elements mounted is N (where N is an integer equal to or greater than 2), when the electric length of a transmission line 4 between one of N T-branch units 6 which is m-th (where m is a positive integer equal to or less than N−1) when counted from the start point of the path A, and another one of the N T-branch units 6 which is (m+1)-th when counted from the start point of the path A, is equal to that of a transmission line 8 between one of N T-branch units 10 which is m-th when counted from the end point of the path B, and another one of the N T-branch units 10 which is (m+1)-th when counted from the end point of the path B, all of the phases of the signals appearing at N output terminals 16 are equal.
The T-branch units 6 correspond to the T-branch units 6a to 6c shown in
In Embodiment 1, as a layout requirement imposed on the in-phase corporate-feed circuit, there is provided only a requirement to equalize the electric length of the transmission line 4 between one of the N T-branch units 6 which is m-th when counted from the start point of the path A, and another one of the N T-branch units 6 which is (m+1)-th when counted from the start point of the path A, to that of the transmission line 8 between one of the N T-branch units 10 which is m-th when counted from the end point of the path B, and another one of the N T-branch units 10 which is (m+1)-th when counted from the end point of the path B.
Therefore, it is not necessary to connect plural power dividers in the shape of a binary tree by using transmission lines, unlike in the case of an in-phase corporate-feed circuit having a circuit configuration of tournament type, and what is necessary is only to connect the N circuit elements 17 by using the transmission lines 4 and 8 having equal electric lengths.
For this reason, the in-phase corporate-feed circuit can be formed in a space smaller than that in which an in-phase corporate-feed circuit having a circuit configuration of tournament type is formed, and downsizing of the circuit size can be achieved.
In a case in which transmitters connected to plural element antennas are arranged at unequal intervals, and in a case in which the number of element antennas is large, the advantage of being able to achieve downsizing of the circuit size is particularly great.
Particularly,
In
Further, in the example shown in
In
In the case of an in-phase corporate-feed circuit having a circuit configuration of tournament type, seven power dividers are connected in the shape of a binary tree by using transmission lines 4 and 8, as shown in
Particularly in a case in which the transmission lines 4 and 8 consist of coaxial cables or waveguides, because it is difficult to bend these transmission lines deeply, it is necessary to ensure a space spreading out greatly in two dimensions. In the example shown in
In contrast with this, because in the case of the in-phase corporate-feed circuit according to Embodiment 1, the layout requirement imposed on the in-phase corporate-feed circuit is eased as compared with the case of an in-phase corporate-feed circuit having a circuit configuration of tournament type, eight circuit elements 17 can be arranged even in a straight line, as shown in
As is clear from the above description, according to Embodiment 1, because as the layout requirement imposed on the in-phase corporate-feed circuit, there is provided only a layout requirement to equalize the electric length of the transmission line 4 between one of the N T-branch units 6 which is m-th when counted from the start point of the path A, and another one of the T-branch units 6 which is (m+1)-th when counted from the start point of the path A, to that of the transmission line 8 between one of the N T-branch units 10 which is m-th when counted from the end point of the path B, and another one of the T-branch units 10 which is (m+1)-th when counted from the end point of the path B, there is provided an advantage of being able to achieve downsizing of the circuit size.
Although in Embodiment 1 the example in which the electric lengths of the transmission lines 4b and 8c at the angular frequency ω are equal, and the electric lengths of the transmission lines 4c and 8b at the angular frequency ω are equal is shown, the physical lengths of the transmission lines 4b and 8c can be equal or different and the physical lengths of the transmission lines 4c and 8b can be equal or different.
For example, in a case in which the dielectric constants of two transmission lines are equal, the electric lengths of the two transmission lines at the angular frequency ω are equal, and the physical lengths of the two transmission lines are equal. In contrast, in a case in which the dielectric constants of two transmission lines are different, when the electric lengths of the two transmission lines at the angular frequency ω are equal, the physical lengths of the two transmission lines are different.
In Embodiment 1, the example in which the input impedances of the mixers 13a to 13c are high is explained.
However, in a case in which the input impedances of the mixers 13a to 13c are not high, for example, in a case in which the input impedances of the mixers 13a to 13c are designed to be 50Ω, or in a case in which the input capacitances of the mixers are so large that they cannot be neglected, an impedance mismatch occurs in each of the T-branch units 6a to 6c and 10a to 10c. More specifically, there occurs a phenomenon in which at each of the T-branch units 6a to 6c and 10a to 10c, a part of a signal is reflected, and a signal flows through the path A or the path B in the opposite direction.
In this case, there occurs a phenomenon in which at each of the T-branch units 6a to 6c and 10a to 10c, a signal flowing through the path A or the path B in the forward direction and a signal flowing through the path A or the path B in the opposite direction overlap, and, as a result, the phases of the signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c are shifted from those given by the above-mentioned equation (1).
To solve such a problem, in the case in which the input impedances of the mixers 13a to 13c are not high, what is necessary is just to connect circuits each having a high input impedance between the T-branch units 6a to 6c and 10a to 10c and the mixers 13a to 13c.
In the example shown in
As each of the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2, for example, a voltage follower using an operational amplifier can be used. A voltage follower has a high input impedance, and is used as a buffer having a voltage amplification rate of 1.
However, the voltage amplification rate does not necessarily have to be 1, and another circuit having a voltage amplification rate greater than 1 or less than 1 can be used.
As mentioned above, by connecting the amplifiers 18a-1 to 18c-1 between the output terminals 7a to 7c of the T-branch units 6a to 6c and the input terminals 14a-1 to 14c-1 of the mixers 13a to 13c, and also connecting the amplifiers 18c-2 to 18a-2 between the output terminals 11a to 11c of the T-branch units 10a to 10c and the input terminals 14c-2 to 14a-2 of the mixers 13c to 13a, an impedance mismatch can be prevented from occurring at each of the T-branch units 6a to 6c and 10a to 10c even in the case in which the input impedances of the mixers 13a to 13c are not high.
It is desirable to connect directly between the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c, and the input terminals of the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2, not via any transmission lines.
Although in Embodiment 1 the example in which signals in phase are outputted from the two output terminals of the power divider 3 is shown, the phases of the signals outputted from the two output terminals can be different.
It is clear from the above-mentioned equation (2) that because it is clear that the phases of the signals outputted from the output terminals 16a to 16c are equal even if the electric length 81 of the transmission line 4a at the angular frequency ω differs from the electric length θ4 of the transmission line 8a at the angular frequency ω, the phases of the signals outputted from the two output terminals of the power divider 3 can be different.
As the power divider 3 that outputs signals having different phases from the two output terminals, for example, a 90 degree hybrid, a 180 degree hybrid, or the like can be considered.
Although in Embodiment 1 the example of using the T-branch units 6a, 6b, and 6c as the first T-branch circuits, and using the T-branch units 10a to 10c as the second branch circuits is shown, directional couplers can be used instead of the T-branch units 6a to 6c and 10a to 10c.
In a case of using the directional coupler 21 having four terminals, it is assumed that a part of a signal inputted from a terminal 22a is outputted from a terminal 22b, and the remaining part of the signal is outputted from a terminal 22c, but is not outputted from a terminal 22d. It is further assumed that a part of a signal inputted from the terminal 22c is outputted from the terminal 22d, and the remaining signal is outputted from the terminal 22a, but is not outputted from the terminal 22b.
The directional coupler 23 having three terminals is the one in which the terminal 22d is removed from the directional coupler 21 having the four terminals.
For example, by bringing each of the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c into correspondence with the terminal 22b of a directional coupler 21 or 23, and connecting the terminal 22a to a transmission line on an input side and also connecting the terminal 22c to a transmission line on an output side, the same operations as those performed by the T-branch units 6a to 6c and 10a to 10c can be implemented.
In Embodiment 1, the example in which the signal generator 2 generates a signal is shown. This signal generator 2 can vary the frequency of the signal generated thereby with time.
Even if the frequency of the signal generated by the signal generator 2 varies with time, all of the phases of the signals appearing at the output terminals 16a to 16c are equal at each time point.
Embodiment 2In
Although in the example shown in
Hereafter, an embodiment configured in this way will be explained as Embodiment 2 by using
A transmission line 31a-1 has an end connected to an amplifier 18a-1, and another end connected to an input terminal 14a-1 of a mixer 13a.
A transmission line 31a-2 has an end connected to an amplifier 18a-2, and another end connected to an input terminal 14a-2 of the mixer 13a.
A transmission line 31b-1 has an end connected to an amplifier 18b-1, and another end connected to an input terminal 14b-1 of a mixer 13b.
A transmission line 31b-2 has an end connected to an amplifier 18b-2, and another end connected to an input terminal 14b-2 of the mixer 13b.
A transmission line 31c-1 has an end connected to an amplifier 18c-1, and another end connected to an input terminal 14c-1 of a mixer 13c.
A transmission line 31c-2 has an end connected to an amplifier 18c-2, and another end connected to an input terminal 14c-2 of the mixer 13c.
A transmission line 32a has an end connected to the mixer 13a, and another end connected to a filter 15a.
A transmission line 32b has an end connected to the mixer 13b, and another end connected to a filter 15b.
A transmission line 32c has an end connected to the mixer 13c, and another end connected to a filter 15c.
Next, operations will be explained.
It is assumed in Embodiment 2 that the electric lengths of the transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2 and the electric lengths of the transmission lines 32a, 32b, and 32c are as follows.
The electric length of the transmission line 31a-1 at an angular frequency ω=θ5
The electric length of the transmission line 31b-1 at the angular frequency ω=θ6
The electric length of the transmission line 31c-1 at the angular frequency ω=θ7
The electric length of the transmission line 31a-2 at the angular frequency ω=θ8
The electric length of the transmission line 31b-2 at the angular frequency ω=θ9
The electric length of the transmission line 31c-2 at the angular frequency ω=θ10
The electric length of each of the transmission lines 32a, 32b, and 32c at the angular frequency ω=θ11
It is further assumed that a relationship shown by the following equation (3) is established among the electric lengths θ5, θ6, θ7, θ8, θ9, and θ10 of the transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2.
θ5+θ8=θ6+θ9=θ7+θ10=α (α is a constant) (3)
More specifically, there is a relationship in which the sum (θ5+θ8) of the electric lengths of the transmission lines 31a-1 and 31a-2, the sum (θ6+θ9) of the electric lengths of the transmission lines 31b-1 and 31b-2, and the sum (θ7+θ10) of the electric lengths of the transmission lines 31c-1 and 31c-2 are equal.
When a signal generator 2 generates a signal, a power divider 3 of a signal generating circuit 1 divides the power of the signal into two parts and outputs signals in phase to a transmission line 4 and a transmission line 8, like that according to above-mentioned Embodiment 1.
The signal outputted from the power divider 3 to the transmission line 4 passes through T-branch units 6a to 6c and is terminated by a terminator 5.
Further, the signal outputted from the power divider 3 to the transmission line 8 passes through T-branch units 10a to 10c and is terminated by a terminator 9.
At this time, when a signal is inputted from an input port IN, each of the T-branch units 6a to 6c inserted onto the transmission line 4 outputs a part of the signal to a corresponding one of output terminals 7a to 7c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
Further, when a signal is inputted from an input port IN, each of the T-branch units 10a to 10c inserted onto the transmission line 8 outputs a part of the signal to a corresponding one of output terminals 11a to 11c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
Because the input impedances of the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 are high, voltages appear at the output terminals 7a to 7c and 11c to 11a, but no currents flow toward the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2.
The phases of the signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c are shown by the above-mentioned equation (1), and all of the phases of these signals differ from one another, like in the case of above-mentioned Embodiment 1.
The amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 amplify the voltages of the signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c, and output the signals whose voltages are amplified thereby to the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2.
When a signal passing through the transmission line 31a-1 is inputted from the input terminal 14a-1 and a signal passing through the transmission line 31a-2 is inputted from the input terminal 14a-2, the mixer 13a mixes the two signals inputted thereto and outputs a mixed signal to the transmission line 32a.
When a signal passing through the transmission line 31b-1 is inputted from the input terminal 14b-1 and a signal passing through the transmission line 31b-2 is inputted from the input terminal 14b-2, the mixer 13b mixes the two signals inputted thereto and outputs a mixed signal to the transmission line 32b.
When a signal passing through the transmission line 31c-1 is inputted from the input terminal 14c-1 and a signal passing through the transmission line 31c-2 is inputted from the input terminal 14c-2, the mixer 13c mixes the two signals inputted thereto and outputs a mixed signal to the transmission line 32c.
When receiving the mixed signal from the mixer 13a via the transmission line 32a, the filter 15a prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15a and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16a.
When receiving the mixed signal from the mixer 13b via the transmission line 32b, the filter 15b prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15b and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16b.
When receiving the mixed signal from the mixer 13c via the transmission line 32c, the filter 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal. As a result, the component passing through the filter 15c and having a phase which is the sum of the phases of the two signals is outputted from an output terminal 16c.
The phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (4).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ4+θ3+θ2+θ8)+θ11=2 ωt+θ1+θ2+θ3+θ4+θ5+θ8+θ11
Output terminal 16b: (ωt+θ1+θ2+θ6)+(ωt+θ4+θ3+θ9)+θ11=2 ωt+θ1+θ2+θ3+θ4+θ6+θ9+θ11
Output terminal 16c: (ωt+θ1+θ2+θ3+θ7)+(ωt+θ4+θ10)+θ11=2 ωt+θ1+θ2+θ3+θ4+θ7+θ10+θ11 (4)
Because it is seen from the equation (3) that θ5+θ8=θ6+θ9=θ7+θ10=α, all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are shown by the following equation (5), and equal.
2 ωt+θ1+θ2+θ3+θ4+α+θ11 (5)
Therefore, even in a case in which the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 are arranged separately from the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c, and it is therefore necessary to connect between the amplifiers and the input terminals by using the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, the signals in phase can be outputted from the output terminals 16a to 16c of the circuit elements 17a to 17c by simply causing the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2 to have a relationship shown by the equation (3), in addition to equalizing the electric lengths of the transmission lines between circuit elements 17.
Embodiment 3Although in above-mentioned Embodiment 1 the in-phase corporate-feed circuit in which the frequency of the signal appearing at each of the output terminals 16a to 16c of the circuit elements 17a to 17c is twice as high as that of the signal generated by the signal generator 2 is shown, an in-phase corporate-feed circuit in which the frequency of a signal appearing at each of output terminals 16a to 16c of circuit elements 17a to 17c is equal to that of a signal generated by a signal generator 2 will be explained in Embodiment 3.
In Embodiment 3, a signal generating circuit 1 includes the signal generator 2 and a ½ frequency divider 41.
The ½ frequency divider 41 reduces the frequency of the signal generated by the signal generator 2 to one-half of the frequency and, after that, divides the signal into two signals, and outputs one of the signals after division to a noninverting output terminal 42 and outputs the other one of the signals after division to an inverting output terminal 43.
The phase of the signal outputted from the noninverting output terminal 42 of the ½ frequency divider 41 and the phase of the signal outputted from the inverting output terminal 43 differ from each other by 180 degrees.
Although in
Further, although in
Next, operations will be explained.
When the signal generator 2 generates a signal, the ½ frequency divider 41 of the signal generating circuit 1 reduces the frequency of the signal to one-half of the frequency and, after that, divides the signal into two signals, and outputs one of the signals after division to the noninverting output terminal 42 and outputs the other one of the signals after division to the inverting output terminal 43.
When the angular frequency of the signal outputted from the signal generator 2 is ω, and it is assumed that, at a time t, the voltage of the signal outputted from the signal generator 2 is expressed by cos(ωt), the voltage of the signal outputted from the noninverting output terminal 42 of the ½ frequency divider 41 is expressed by cos (0.5 ωt) and the voltage of the signal outputted from the inverting output terminal 43 of the ½ frequency divider 41 is expressed by cos(0.5 ωt+π).
It is assumed in Embodiment 3 that the electric length of the transmission line 4a at an angular frequency 0.5∫ is θ1, the electric length of a transmission line 4b at the angular frequency 0.5ω is θ2, and the electric length of a transmission line 4c at the angular frequency 0.5ω is θ3.
It is further assumed that the electric length of the transmission line 8a at the angular frequency 0.5ω is θ4, the electric length of a transmission line 8b at the angular frequency 0.5ω is θ3, and the electric length of a transmission line 8c at the angular frequency 0.5ω is θ2.
A signal outputted from the ½ frequency divider 41 to a transmission line 4 passes through T-branch units 6a to 6c and is terminated by a terminator 5.
Further, a signal outputted from the ½ frequency divider 41 to a transmission line 8 passes through T-branch units 10a to 10c and is terminated by a terminator 9.
At this time, when a signal is inputted from an input port IN, each of the T-branch units 6a to 6c inserted onto the transmission line 4 outputs a part of the signal to a corresponding one of output terminals 7a to 7c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
Further, when a signal is inputted from an input port IN, each of the T-branch units 10a to 10c inserted onto the transmission line 8 outputs a part of the signal to a corresponding one of output terminals 11a to 11c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
Mixers 13a to 13c of phase adding circuits 12a to 12c have input terminals 14a-1 to 14c-1 connected to the output terminals 7a to 7c, and input terminals 14a-2 to 14c-2 connected to the output terminals 11c to 11a.
However, because the input impedances of the mixers 13a to 13c are high, voltages appear at the output terminals 7a to 7c and 11c to 11a, but no currents flow toward the input terminal 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c.
The phases of the signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c are shown by the following equation (6), and all of the phases of these signals differ from one another.
Output terminal 7a:0.5 ωt+θ1
Output terminal 7b:0.5 ω+θ1+θ2
Output terminal 7c:0.5 ωt+θ1+θ2+θ3
Output terminal 11a:0.5 ωt+θ4+π
Output terminal 11b:0.5 ωt+θ4+θ3+π
Output terminal 11c:0.5 ωt+θ4+θ3+θ2+π (6)
Because the voltage of the signal outputted from the inverting output terminal 43 of the ½ frequency divider 41 is expressed by cos(0.5 ωt+π), π is included in the phase of the signal appearing at each of the output terminals 11a to 11c of the T-branch units 10a to 10c.
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from the output terminals 16a to 16c.
The phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are shown by the following equation (7).
Output terminal 16a: (0.5 ωt+θ1)+(0.5 ωt+θ4+θ3+θ2+π)=ωt+θ1+θ2+θ3+θ4+π
Output terminal 16b: (0.5 ωt+θ1+θ2)+(0.5 ωt+θ4+θ3+π)=ωt+θ1+θ2+θ3+θ4+π
Output terminal 16c: (0.5 ωt+θ1+θ2+θ3)+(0.5 ωt+θ4+π)=ωt+θ1+θ2+θ3+θ4+π (7)
As is clear from the equation (7), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
Therefore, even in the case of using the ½ frequency divider 41 instead of the power divider 3, the signals in phase can be outputted from the output terminals 16a to 16c of the circuit elements 17a to 17c, like in the case of above-mentioned Embodiment 1. Further, the signals each having a frequency equal to the frequency of the signal generated by the signal generator 2 can be outputted from the output terminals 16a to 16c of the circuit elements 17a to 17c. More specifically, the angular frequency ω of the signal generated by the signal generator 2 can be made to match the angular frequency ω of the signals outputted from the output terminals 16a to 16c of the circuit elements 17a to 17c.
Although in Embodiment 3 the example in which the ½ frequency divider 41 is used instead of the power divider 3, the noninverting output terminal 42 of the ½ frequency divider 41 is connected to the transmission line 4a, and the inverting output terminal 43 is connected to the transmission line 8a is shown, the noninverting output terminal 42 or the inverting output terminal 43 of the ½ frequency divider 41 can be connected to a power divider 3, and the power divider 3 can divide the signal outputted from the ½ frequency divider 41 to signals to the transmission lines 4a and 8a, as shown in
Further, a 1/N frequency divider (where N is an integer or a rational number) can be used instead of the ½ frequency divider 41. However, in this case, the angular frequency of the signals outputted from the output terminals 16a to 16c of the circuit elements 17a to 17c is 2×ω/N, and differs from the angular frequency ω of the signal generated by the signal generator 2. The 1/N frequency divider can be a fixed frequency divider or a variable frequency divider.
Further, a direct digital synthesizer can be used instead of the ½ frequency divider 41. Hereafter, the direct digital synthesizer is referred to as the DDS (Direct Digital Synthesizer).
The DDS has a control signal input terminal, a clock signal input terminal, and an output terminal. Because the DDS can vary the frequency of a clock signal inputted from the clock signal input terminal in accordance with a control signal inputted from the control signal input terminal, and output the clock signal after frequency variation from the output terminal, the DDS can be provided with a function equivalent to that of the variable frequency divider.
In addition, the variable frequency divider or the DDS which is connected instead of the ½ frequency divider 41 can be configured to vary the frequency of the signal outputted from the output terminal with time. Even if the frequency is varied with time, all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c can be made to be equal at each time point, like in the case of above-mentioned Embodiment 1.
Although in Embodiment 3 the variant of above-mentioned Embodiment 1 in which the signal generating circuit 1 includes the signal generator 2 and the ½ frequency divider 41 is explained, above-mentioned Embodiment 2 can be modified by applying the signal generating circuit 1 including the signal generator 2 and the ½ frequency divider 41 to above-mentioned Embodiment 2.
Embodiment 4Although in above-mentioned Embodiments 1 and 2 the example in which the amplifiers 18a-1 to 18c-1 are connected between the output terminals 7a to 7c of the T-branch units 6a to 6c and the input terminals 14a-1 to 14c-1 of the mixers 13a to 13c, and the amplifiers 18a-2 to 18c-2 are connected between the output terminals 11c to 11a of the T-branch units 10c to 10a and the input terminals 14a-2 to 14c-2 of the mixers 13a to 13c is shown, attenuators can be further connected between the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 and the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c.
An attenuator 51a-1 is connected between an amplifier 18a-1 and an input terminal 14a-1 of a mixer 13a, and attenuates the amplitude of a signal outputted from the amplifier 18a-1 and provides the signal after amplitude attenuation for the input terminal 14a-1 of the mixer 13a.
An attenuator 51a-2 is connected between an amplifier 18a-2 and an input terminal 14a-2 of the mixer 13a, and attenuates the amplitude of a signal outputted from the amplifier 18a-2 and provides the signal after amplitude attenuation for the input terminal 14a-2 of the mixer 13a.
An attenuator 51b-1 is connected between an amplifier 18b-1 and an input terminal 14b-1 of a mixer 13b, and attenuates the amplitude of a signal outputted from the amplifier 18b-1 and provides the signal after amplitude attenuation for the input terminal 14b-1 of the mixer 13b.
An attenuator 51b-2 is connected between an amplifier 18b-2 and an input terminal 14b-2 of the mixer 13b, and attenuates the amplitude of a signal outputted from the amplifier 18b-2 and provides the signal after amplitude attenuation for the input terminal 14b-2 of the mixer 13b.
An attenuator 51c-1 is connected between an amplifier 18c-1 and an input terminal 14c-1 of a mixer 13c, and attenuates the amplitude of a signal outputted from the amplifier 18c-1 and provides the signal after amplitude attenuation for the input terminal 14c-1 of the mixer 13c.
An attenuator 51c-2 is connected between an amplifier 18c-2 and an input terminal 14c-2 of the mixer 13c, and attenuates the amplitude of a signal outputted from the amplifier 18c-2 and provides the signal after amplitude attenuation for the input terminal 14c-2 of the mixer 13c.
Next, operations will be explained.
For example, in a case in which the amplitudes of two signals after division by a power divider 3 are not equal, and in a case in which the amplitudes of the two signals after division by the power divider 3 are attenuated depending on the lengths of transmission lines 4a to 4c and 8a to 8c because there is a loss in each of the transmission lines 4a to 4c and 8a to 8c, the combination of the amplitudes of the two signals inputted to each of the mixers 13a to 13c is different.
When the combination of the amplitudes of the two signals inputted to each of the mixers 13a to 13c is different, there is a case in which the operating points of nonlinear elements which construct the mixers 13a to 13c are different, and the phases of signals outputted from the mixers 13a to 13c are different even if the sum of the phases of the two signals inputted to each of the mixers 13a to 13c is equal.
In Embodiment 4, by appropriately setting the amounts of attenuation of the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2, the combination of the amplitudes of the two signals inputted to each of the mixers 13a to 13c is adjusted to be equal. For example, when the amplitude of the signal inputted to the input terminal 14a-1 of the mixer 13a is A and the amplitude of the signal inputted to the input terminal 14a-2 is B, the amplitude of the signal inputted to each of the input terminals 14b-1 and 14c-1 of the mixers 13b and 13c is adjusted to be A and the amplitude of the signal inputted to each of the input terminals 14b-2 and 14c-2 is adjusted to be B.
As a result, because the operating points of the nonlinear elements which construct the mixers 13a to 13c are the same as one another, the phases of the signals outputted from the mixers 13a to 13c can be made to be equal.
Although in Embodiment 4 the example in which the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2 that attenuate the amplitudes of the signals outputted from the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 are disposed is shown, the combination of the amplitudes of the two signals inputted to each of the mixers 13a to 13c can be made to be equal without disposing the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2, by appropriately setting the gains of the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2.
Although in Embodiment 4 the example in which the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2 that attenuate the amplitudes of the signals outputted from the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2 are disposed is shown, the combination of the amplitudes of the two signals inputted to each of the mixers 13a to 13c can be made to be equal without disposing the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2, by inserting amplifiers 52a, 52b, and 52c onto the transmission lines 4a, 4b, and 4c and also inserting amplifiers 53a, 53b, and 53c onto the transmission lines 8a, 8b, and 8c, as shown in
Although in Embodiment 4 the example in which, in the configuration shown in
Further, in the configuration shown in
Although in Embodiment 4 the example in which the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2 are connected between the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2, and the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c is shown, the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2 can also be applied to the in-phase corporate-feed circuit shown in any of above-mentioned Embodiments 1 to 3 as long as the in-phase corporate-feed circuit is equipped with the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2.
Embodiment 5Although in above-mentioned Embodiments 1 to 4 the example in which the T-branch units 6a to 6c and 10a to 10c are inserted onto the transmission lines 4 and 8 is shown, circulators, instead of the T-branch units 6a to 6c and 10a to 10c, can be inserted onto the transmission lines 4 and 8.
Each of the circulators 61 and 63 is a type of non-reciprocal circuit having a property of transmitting a signal only in a predetermined direction, but not transmitting any signal in an opposite direction.
Each of the circulators 61 and 63 has three terminals 65a, 65b, and 65c. A signal inputted from the terminal 65a is outputted from the terminal 65b, a signal inputted from the terminal 65b is outputted from the terminal 65c, and a signal inputted from the terminal 65c is outputted from the terminal 65a, but no signals are transmitted in opposite directions.
A circulator 61a has a terminal 65a connected to a transmission line 4a, a terminal 65b connected to an output terminal 62a, and a terminal 65c connected to a transmission line 4b.
A circulator 61b has a terminal 65a connected to the transmission line 4b, a terminal 65b connected to an output terminal 62b, and a terminal 65c connected to a transmission line 4c.
A circulator 61c has a terminal 65a connected to the transmission line 4c, a terminal 65b connected to an output terminal 62c, and a terminal 65c connected to a terminator 5.
The output terminal 62a is connected to the terminal 65b of the circulator 61a, and a transmission line 31a-1.
The output terminal 62b is connected to the terminal 65b of the circulator 61b, and a transmission line 31b-1.
The output terminal 62c is connected to the terminal 65b of the circulator 61c, and a transmission line 31c-1.
The circulators 61a, 61b, and 61c construct first T-branch circuits.
A circulator 63a has a terminal 65a connected to a transmission line 8a, a terminal 65b connected to an output terminal 64a, and a terminal 65c connected to a transmission line 8b.
A circulator 63b has a terminal 65a connected to the transmission line 8b, a terminal 65b connected to an output terminal 64b, and a terminal 65c connected to a transmission line 8c.
A circulator 63c has a terminal 65a connected to the transmission line 8c, a terminal 65b connected to an output terminal 64c, and a terminal 65c connected to a terminator 9.
The output terminal 64a is connected to the terminal 65b of the circulator 63a, and a transmission line 31c-2.
The output terminal 64b is connected to the terminal 65b of the circulator 63b, and a transmission line 31b-2.
The output terminal 64c is connected to the terminal 65b of the circulator 63c, and a transmission line 31a-2.
The circulators 63a, 63b, and 63c construct second branch circuits.
Next, operations will be explained.
It is assumed in Embodiment 5 that the electric lengths of the transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2 are as follows.
The electric length of the transmission line 31a-1 at an angular frequency ω=θ5
The electric length of the transmission line 31b-1 at the angular frequency ω=θ6
The electric length of the transmission line 31c-1 at the angular frequency ω=θ7
The electric length of the transmission line 31a-2 at the angular frequency ω=θ5
The electric length of the transmission line 31b-2 at the angular frequency ω=θ6
The electric length of the transmission line 31c-2 at the angular frequency ω=θ7
Thus, there is a relationship in which the electric lengths of the transmission lines 31a-1 and 31a-2 are θ5 and equal, the electric lengths of the transmission lines 31b-1 and 31b-2 are θ6 and equal, and the electric lengths of the transmission lines 31c-1 and 31c-2 are θ7 and equal.
When a signal generator 2 generates a signal, a power divider 3 of a signal generating circuit 1 divides the power of the signal into two parts and outputs signals in phase to a transmission line 4 and a transmission line 8, like that according to above-mentioned Embodiment 1.
When the signal outputted from the power divider 3 is provided for the terminal 65a, the circulator 61a outputs this signal from the terminal 65b. The signal outputted from the terminal 65b of the circulator 61a is transmitted to an input terminal 14a-1 of a mixer 13a via the output terminal 62a and the transmission line 31a-1. However, because the input impedance of the mixer 13a is high, the signal which reaches the input terminal 14a-1 of the mixer 13a is reflected and transmitted to the terminal 65b of the circulator 61a via the transmission line 31a-1 and the output terminal 62a.
When the signal reflected by the mixer 13a is provided for the terminal 65b, the circulator 61a outputs this signal from the terminal 65c. The signal outputted from the terminal 65c of the circulator 61a is transmitted to the terminal 65a of the circulator 61b via the transmission line 4b.
The circulator 61b operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 61a to the mixer 13b via the output terminal 62b and the transmission line 31b-1 and, after that, outputs the signal which is reflected by the mixer 13b and returns thereto to the circulator 61c via the transmission line 4c.
The circulator 61c operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 61b to the mixer 13c via the output terminal 62c and the transmission line 31c-1 and, after that, outputs the signal which is reflected by the mixer 13c and returns thereto to the terminator 5.
The circulator 63a operates in the same way as the circulator 61a, and outputs the signal outputted from the power divider 3 to the mixer 13c via the output terminal 64a and the transmission line 31c-2 and, after that, outputs the signal which is reflected by the mixer 13c and returns thereto to the circulator 63b via the transmission line 8b.
The circulator 63b operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 63a to the mixer 13b via the output terminal 64b and the transmission line 31b-2 and, after that, outputs the signal which is reflected by the mixer 13b and returns thereto to the circulator 63c via the transmission line 8c.
The circulator 63c operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 63b to the mixer 13a via the output terminal 64c and the transmission line 31a-2 and, after that, outputs the signal which is reflected by the mixer 13a and returns thereto to the terminator 9.
The phases of the signals appearing at the input terminals 14a-1, 14b-1, 14c-1, 14a-2, 14b-2, and 14c-2 of the mixers 13a to 13c are shown by the following equation (8), and all of the phases of these signals differ from one another.
Input terminal 14a-1:ωt+θ1+θ5
Input terminal 14b-1:ωt+θ1+2×θ5+θ2+θ6
Input terminal 14c-1:ωt+θ1+2×θ5+θ2+2×θ6+θ3+θ7
Input terminal 14a-2:ωt+θ4+2×θ7+θ3+2×θ6+θ2+θ5
Input terminal 14b-2:ωt+θ4+2×θ7+θ3+θ6
Input terminal 14c-2:ωt+θ4+θ7 (8)
Each of the mixers 13a to 13c mixes the two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
The phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (9).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ4+2×θ7+θ3+2×θ6+θ2+θ5)=2 ωt+θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7)
Output terminal 16b: (ωt+θ1+2×θ5+θ2+θ6)+(ωt+θ4+2×θ7+θ3+θ6)=2 ωt+θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7)
Output terminal 16c: (ωt+θ1+2×θ5+θ2+2×θ6+θ3+θ7)+(ωt+θ4+θ7)=2 ωt=θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7) (9)
As is clear from the equation (9), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
In the case of using the circulators 61a to 61c and 63a to 63c, like in the case of Embodiment 5, in addition to equalizing the electric lengths of the transmission lines between circuit elements 17, the electric lengths of the transmission lines 31a-1 and 31a-2 are equalized, the electric lengths of the transmission lines 31b-1 and 31b-2 are equalized, and the electric lengths of the transmission lines 31c-1 and 31c-2 are equalized. However, in the case where the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2 are not disposed, the electric lengths of the transmission lines between circuit elements 17 may be preferably equalized, as shown in above-mentioned Embodiment 1.
Embodiment 6Although in above-mentioned Embodiment 1 the example in which the in-phase corporate-feed circuit includes the transmission line 4 and the transmission line 8, and the power divider 3 divides the signal generated by the signal generator 2 into signals to the transmission line 4 and the transmission line 8 is shown, the in-phase corporate-feed circuit can be configured to include a transmission line which consists of a forward path and a return path, thereby eliminating the need for the power divider 3 and achieving further downsizing of the circuit size.
A transmission line 70 is one along which signals propagate bidirectionally. This transmission line consists of, for example, a coaxial cable, a waveguide, a microstrip line formed on a printed circuit board, or the like, and includes transmission lines 70a, 70b, 70c, 70d, 70e, and 70f.
A path which consists of the transmission lines 70a, 70b, and 70c, and a first half extending up to a halfway point of the transmission line 70d is a forward path A, and a path which consists of a second half extending from the halfway point of the transmission line 70d, and the transmission lines 70e and 70f is a return path B.
In Embodiment 6, T-branch units 6a, 6b, and 6c are inserted onto the forward path A of the transmission line 70, and T-branch units 10a, 10b, and 10c are inserted onto the return path B of the transmission line 70.
In Embodiment 6, the angular frequency of a signal outputted from a signal generator 2 is ω, and it is assumed that, at a time t, the voltage of the signal outputted from the signal generator 2 is expressed by cos (ωt).
Further, it is assumed that the electric length of the transmission line 70a at the angular frequency ω is θ1, the electric length of the transmission line 70b at the angular frequency ω is θ2, and the electric length of the transmission line 70c at the angular frequency ω is θ3.
In addition, it is assumed that the electric length of the transmission line 70d at the angular frequency ω is θ4, the electric length of the transmission line 70e at the angular frequency ω is θ3, and the electric length of the transmission line 70f at the angular frequency ω is θ2.
Therefore, the electric length θ2 of the transmission line 70b between the T-branch unit 6a which is first when counted from an end of the transmission line 70 connected to the signal generator 2, i.e., from a start point of the forward path A, and the T-branch unit 6b which is second when counted from the start point of the forward path A, is equal to the electric length θ2 of the transmission line 70f between the T-branch unit 10c which is first when counted from another end of the transmission line 70 connected to a terminator 5, i.e., from an end point of the return path B, and the T-branch unit 10b which is second when counted from the end point of the return path B.
Further, the electric length θ3 of the transmission line 70c between the T-branch unit 6b which is second when counted from the start point of the forward path A, and the T-branch unit 6c which is third when counted from the start point of the forward path A, is equal to the electric length θ3 of the transmission line 70e between the T-branch unit 10b which is second when counted from the end point of the return path B, and the T-branch unit 10a which is third when counted from the end point of the return path B.
Next, operations will be explained.
In Embodiment 6, for the sake of simplicity, it is assumed that phase variations which are caused by the transmission of signals by the T-branch units 6a to 6c and 10a to 10c, and filters 15a to 15c can be neglected.
It is further assumed that the T-branch unit 10c is connected directly to the terminator 5, not via any transmission line, and mixers 13a to 13c are connected directly to the filters 15a to 15c, not via any transmission lines.
It is further assumed that the input impedances of the mixers 13a to 13c are high.
The signal generator 2 generates a signal and outputs the signal to the transmission line 70a.
The signal outputted from the signal generator 2 to the transmission line 70a passes through the T-branch units 6a to 6c and 10a to 10c, and is terminated by the terminator 5.
At this time, when a signal is inputted from an input port IN, each of the T-branch units 6a to 6c inserted onto the forward path A of the transmission line 70 outputs a part of the signal to a corresponding one of output terminals 7a to 7c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
Further, when a signal is inputted from an input port IN, each of the T-branch units 10a to 10c inserted onto the return path B of the transmission line 70 outputs a part of the signal to a corresponding one of output terminals 11a to 11c because a branch line is disposed for a line connecting between the input port IN and an output port OUT.
The mixers 13a to 13c of phase adding circuits 12a to 12c have input terminals 14a-1 to 14c-1 connected to the output terminals 7a to 7c, and input terminals 14a-2 to 14c-2 connected to the output terminals 11c to 11a.
However, because the input impedances of the mixers 13a to 13c are high, voltages appear at the output terminals 7a to 7c and 11c to 11a, but no currents flow toward the input terminal 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c.
The phases of the signals appearing at the output terminals 7a to 7c and 11a to 11c of the T-branch units 6a to 6c and 10a to 10c are shown by the following equation (10), and all of the phases of these signals differ from one another.
Output terminal 7a:ωt+θ1
Output terminal 7b:ωt+θ1+θ2
Output terminal 7c:ωt+θ1+θ2+θ3
Output terminal 11a:ωt+θ1+θ2+θ3+θ4
Output terminal 11b:ωt+θ1+θ2+2×θ3+θ4
Output terminal 11c:ωt+θ1+2×θ2+2×θ3+θ4 (10)
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of the filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
The phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (11).
Output terminal 16a: (ωt+θ1)+(ωt+θ1+2×θ2+2×θ3+θ4)=2×(ωt+θ1+θ2+θ3)+θ4
Output terminal 16b: (ωt+θ1+θ2)+(ωt+θ1+θ2+2×θ3+θ4)=2×(ωt+θ1+θ2+θ3)+θ4
Output terminal 16c: (ωt+θ1+θ2+θ3)+(ωt+θ1+θ2′θ2+θ3+θ4)=2×(ωt+θ1+θ2+θ3)+θ4 (11)
As is clear from the equation (11), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
Also in Embodiment 6, as a layout requirement imposed on the in-phase corporate-feed circuit, only a requirement to equalize the electric lengths of the transmission lines between circuit elements 17 is provided, like in the case of above-mentioned Embodiment 1.
Therefore, because it is not necessary to connect plural power dividers in the shape of a binary tree by using transmission lines, unlike in the case of an in-phase corporate-feed circuit having a circuit configuration of tournament type, the in-phase corporate-feed circuit can be formed in a space smaller than that in which an in-phase corporate-feed circuit having a circuit configuration of tournament type is formed, and downsizing of the circuit size can be achieved.
In the case of above-mentioned Embodiment 1, because the in-phase corporate-feed circuit includes the transmission line 4 and the transmission line 8, and the power divider 3 divides the signal generated by the signal generator 2 into signals to the transmission line 4 and the transmission line 8, it is necessary to route the transmission line 4 and the transmission line 8 up to the two circuit elements 17 arranged at both the ends among the eight circuit elements 17 which are arranged in a straight line, as shown in
In contrast with this, in the case of Embodiment 6, because what is necessary is to connect the signal generator 2 to the end of the single transmission line 70, the routing length of the transmission line 70 can be shortened. Further, the power divider 3 is unnecessary. Therefore, the circuit size of the in-phase corporate-feed circuit can be reduced to a size smaller than that of the in-phase corporate-feed circuit of Embodiment 1.
Although in Embodiment 6 the transmission line 70a connects between the signal generator 2 and the T-branch unit 6a, the signal generator 2 and the T-branch unit 6a can be connected directly to each other without using the transmission line 70a.
Further, although the transmission line 70d connects between the T-branch unit 6c and the T-branch unit 10a, the T-branch unit 6c and the T-branch unit 10a can be connected directly to each other without using the transmission line 70d.
Although in Embodiment 6 the example of using the T-branch units 6a, 6b, and 6c as the first branch circuits, and also using the T-branch units 10a to 10c as the second branch circuits is shown, directional couplers can be used instead of the T-branch units 6a to 6c and 10a to 10c.
For example, in a case of using such directional couplers 21 or 23 as shown in
Although in Embodiment 6 the example of applying the transmission line 70 along which signals propagate bidirectionally to the in-phase corporate-feed circuit in which the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2, the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2, the amplifiers 52a-1 to 52c-1 and 53a-2 to 53c-2, and so on are not mounted is shown, the transmission line 70 along which signals propagate bidirectionally can be applied to such the in-phase corporate-feed circuits as shown in above-mentioned Embodiments 1 to 4 in each of which some of the following components: the amplifiers 18a-1 to 18c-1 and 18a-2 to 18c-2, the attenuators 51a-1 to 51c-1 and 51a-2 to 51c-2, the amplifiers 52a-1 to 52c-1 and 53a-2 to 53c-2, and so on are mounted.
Embodiment 7Although in above-mentioned Embodiment 6 the example in which the T-branch units 6a to 6c and 10a to 10c are inserted onto the transmission line 70 is shown, circulators, instead of the T-branch units 6a to 6c and 10a to 10c, can be inserted onto the transmission line 70.
In Embodiment 7, it is assumed that the electric length of a transmission line 70a at an angular frequency ω is θ1, the electric length of a transmission line 70b at the angular frequency ω is θ2, and the electric length of a transmission line 70c at the angular frequency ω is θ3, like in the case of above-mentioned Embodiment 6. It is further assumed that the electric length of a transmission line 70d at the angular frequency ω is θ4, the electric length of a transmission line 70e at the angular frequency ω is θ3, and the electric length of a transmission line 70f at the angular frequency ω is θ2.
Further, in Embodiment 7, it is assumed that the electric lengths of transmission lines 31a-1 and 31a-2 at the angular frequency ω are θ5, the electric lengths of transmission lines 31b-1 and 31b-2 at the angular frequency ω are θ6, and the electric lengths of transmission lines 31c-1 and 31c-2 at the angular frequency ω are θ7, like in the case of above-mentioned Embodiment 5.
Next, operations will be explained.
Each of circulators 61a to 61c and 63a to 63c has the same terminals 65a to 65c as those of a circulator shown in
A signal generator 2 generates a signal and outputs the signal to the transmission line 70a.
When the signal outputted from the signal generator 2 is provided for the terminal 65a, the circulator 61a outputs this signal from the terminal 65b. The signal outputted from the terminal 65b of the circulator 61a is transmitted to an input terminal 14a-1 of a mixer 13a via an output terminal 62a and the transmission line 31a-1. However, because the input impedance of the mixer 13a is high, the signal which reaches the input terminal 14a-1 of the mixer 13a is reflected and transmitted to the terminal 65b of the circulator 61a via the transmission line 31a-1 and the output terminal 62a.
When the signal reflected by the mixer 13a is provided for the terminal 65b, the circulator 61a outputs this signal from the terminal 65c. The signal outputted from the terminal 65c is transmitted to the terminal 65a of the circulator 61b via the transmission line 70b.
The circulator 61b operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 61a to a mixer 13b via an output terminal 62b and the transmission line 31b-1 and, after that, outputs the signal which is reflected by the mixer 13b and returns thereto to the circulator 61c via the transmission line 70c.
The circulator 61c operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 61b to a mixer 13c via an output terminal 62c and the transmission line 31c-1 and, after that, outputs the signal which is reflected by the mixer 13c and returns thereto to the circulator 63a via the transmission line 70d.
The circulator 63a operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 61c to the mixer 13c via an output terminal 64a and the transmission line 31c-2 and, after that, outputs the signal which is reflected by the mixer 13c and returns thereto to the circulator 63b via the transmission line 70e.
The circulator 63b operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 63a to the mixer 13b via an output terminal 64b and the transmission line 31b-2 and, after that, outputs the signal which is reflected by the mixer 13b and returns thereto to the circulator 63c via the transmission line 70f.
The circulator 63c operates in the same way as the circulator 61a, and outputs the signal outputted from the circulator 63b to the mixer 13a via an output terminal 64c and the transmission line 31a-2 and, after that, outputs the signal which is reflected by the mixer 13a and returns thereto to a terminator 5.
The phases of the signals appearing at the input terminals 14a-1, 14b-1, 14c-1, 14a-2, 14b-2, and 14c-2 of the mixers 13a to 13c are shown by the following equation (12), and all of the phases of these signals differ from one another.
Input terminal 14a-1:ωt+θ1+θ5
Input terminal 14b-1:ωt+θ1+2×θ5+θ2+θ6
Input terminal 14c-1:ωt+θ1+2×θ5+θ2+2×θ6+θ3+θ7
Input terminal 14a-2:ωt+θ1+3×θ5+2×θ2+4×θ6+2×θ3+4×θ7+θ4
Input terminal 14b-2:ωt+θ1+2×θ5+θ2+3×θ6+2×θ3+4×θ7+θ4
Input terminal 14c-2:ωt+θ1+2×θ5+θ2+2×θ6+θ3+3×θ7+θ4 (12)
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
The phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (13).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ1+3×θ5+2×θ2+4×θ6+2×θ3+4×θ7+θ4)=2×(ωt+θ1+θ2+θ3)+θ4+4×(θ5+θ6+θ7)
Output terminal 16b: (ωt+θ1+2×θ5+θ2+θ6)+(ωt+θ1+2×θ5+θ2+3×θ6+2×θ3+4×θ7+θ4)=2×(ωt+θ1+θ2+θ3)+θ4′4×(θ5+θ6+θ7)
Output terminal 16c: (ωt+θ1+2×θ5+θ2+2×θ6+θ3+θ7)+(ωt+θ1+2×θ5+θ2+2×θ6+θ3+3×θ7+θ4)=2×(ωt+θ1+θ2+θ3)+θ4′4×(θ5+θ6+θ7) (13)
As is clear from the equation (13), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
In Embodiment 7, as layout requirements imposed on the in-phase corporate-feed circuit, only a requirement to equalize the electric lengths of the transmission lines between circuit elements 17, and a requirement to equalize the electric lengths of the transmission lines 31a-1 and 31a-2, equalize the electric lengths of the transmission lines 31b-1 and 31b-2, and equalize the electric lengths of the transmission lines 31c-1 and 31c-2 are provided.
Therefore, because it is not necessary to connect plural power dividers in the shape of a binary tree by using transmission lines, unlike in the case of an in-phase corporate-feed circuit having a circuit configuration of tournament type, the in-phase corporate-feed circuit can be formed in a space smaller than that in which an in-phase corporate-feed circuit having a circuit configuration of tournament type is formed, and downsizing of the circuit size can be achieved.
Embodiment 8Although in above-mentioned Embodiments 1 to 5 the example in which the in-phase corporate-feed circuit includes the two transmission lines 4 and 8 which are physically different is shown, the in-phase corporate-feed circuit can be configured to include a single transmission line along which signals propagate bidirectionally.
A transmission line 80 consists of, for example, a coaxial cable, a waveguide, a microstrip line formed on a printed circuit board, or the like. The transmission line 80 is one along which signals propagate bidirectionally, and has an end connected to a circulator 81a and another end connected to a circulator 82a.
Directional couplers 83a, 83b, and 83c are inserted at points of the transmission line 80, a path through which a signal flows in a first direction, i.e., a path through which a signal flows from the circulator 81a toward the directional coupler 83a→ the directional coupler 83b→ the directional coupler 83c→ the circulator 82a is referred to as a path A, and a path through which a signal flows in a second direction, i.e., a path through which a signal flows from the circulator 82a toward the directional coupler 83c→ the directional coupler 83b→ the directional coupler 83a→ the circulator 81a is referred to as a path B.
Hereafter, a transmission line between the circulator 81a and the directional coupler 83a is denoted by 80a, a transmission line between the directional coupler 83a and the directional coupler 83b is denoted by 80b, a transmission line between the directional coupler 83b and the directional coupler 83c is denoted by 80c, and a transmission line between the directional coupler 83c and the circulator 82a is denoted by 80d. Thus, the transmission line 80 includes the transmission lines 80a, 80b, 80c, and 80d. It is desirable that all of the characteristic impedances of the transmission lines 80a, 80b, 80c, and 80d are equal.
An isolator 81 is a first isolator that includes the circulator 81a and a terminator 9, and that outputs one of signals after division by a power divider 3 to an end of the transmission line 80a and also blocks the transmission of a signal outputted from the end of the transmission line 80a.
The circulator 81a outputs the one of the signals after division by the power divider 3 to the end of the transmission line 80a, and also outputs the signal outputted from the end of the transmission line 80a to the terminator 9.
The circulator 81a has three terminals 65a, 65b, and 65c, as shown in
An isolator 82 is a second isolator that includes the circulator 82a and a terminator 5, and that outputs the other one of the signals after division by the power divider 3 to another end of the transmission line 80d and also blocks the transmission of a signal outputted from the other end of the transmission line 80d.
The circulator 82a outputs the other one of the signals after division by the power divider 3 to the other end of the transmission line 80d, and also outputs the signal outputted from the other end of the transmission line 80d to the terminator 5. The circulator 82a has three terminals 65a, 65b, and 65c, as shown in
Although in
The directional coupler 83a outputs a part of the signal on the path A which is outputted from the power divider 3 to an output terminal 84a-1 (first terminal), and outputs a part of the signal on the path B which is outputted from the power divider 3 to an output terminal 84a-2 (second terminal).
The directional coupler 83a has four terminals, as shown in
The directional coupler 83b outputs a part of the signal on the path A which is outputted from the power divider 3 to an output terminal 84b-1 (first terminal), and outputs a part of the signal on the path B which is outputted from the power divider 3 to an output terminal 84b-2 (second terminal).
The directional coupler 83b has four terminals, as shown in
The directional coupler 83c outputs a part of the signal on the path A which is outputted from the power divider 3 to an output terminal 84c-1 (first terminal), and outputs a part of the signal on the path B which is outputted from the power divider 3 to an output terminal 84c-2 (second terminal).
The directional coupler 83c has four terminals, as shown in
The directional couplers 83a, 83b, and 83c construct branch circuits.
Next, operations will be explained.
In Embodiment 8, it is assumed that the electric lengths of the transmission lines 80a, 80b, 80c, and 80d and the electric lengths of transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2 are as follows.
The electric length of the transmission line 80a at an angular frequency ω=θ1
The electric length of the transmission line 80b at the angular frequency ω=θ2
The electric length of the transmission line 80c at the angular frequency ω=θ3
The electric length of the transmission line 80d at the angular frequency ω=θ4
The electric length of the transmission line 31a-1 at the angular frequency ω=θ5
The electric length of the transmission line 31b-1 at the angular frequency ω=θ6
The electric length of the transmission line 31c-1 at the angular frequency ω=θ7
The electric length of the transmission line 31a-2 at the angular frequency ω=θ8
The electric length of the transmission line 31b-2 at the angular frequency ω=θ9
The electric length of the transmission line 31c-2 at the angular frequency ω=θ10
It is further assumed that a relationship shown by the equation (3) is established among the electric lengths θ5, θ6, θ7, θ8, θ9, and θ10 of the transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2, like in the case of above-mentioned Embodiment 2.
More specifically, there is a relationship in which the sum (θ5+θ8) of the electric lengths of the transmission lines 31a-1 and 31a-2, the sum (θ6+θ9) of the electric lengths of the transmission lines 31b-1 and 31b-2, and the sum (θ7+θ10) of the electric lengths of the transmission lines 31c-1 and 31c-2 are all α and equal.
When a signal generator 2 generates a signal, the power divider 3 of a signal generating circuit 1 divides the power of the signal into two parts and outputs signals in phase to the circulator 81a and the circulator 82a.
When receiving the signal from the power divider 3, the circulator 81a outputs the signal to the end of the transmission line 80a. As a result, the signal outputted from the power divider 3 is transmitted to the transmission line 80 as a signal on the path A.
When receiving the signal from the power divider 3, the circulator 82a outputs the signal to the other end of the transmission line 80d. As a result, the signal outputted from the power divider 3 is transmitted to the transmission line 80 as a signal on the path B.
When a signal on the path A which flows through the transmission line 80a is inputted, the directional coupler 83a outputs a part of the signal to the transmission line 80b, and also outputs the remaining part of the signal to an input terminal 14a-1 of a mixer 13a via the output terminal 84a-1 and the transmission line 31a-1.
Further, when a signal on the path B which flows through the transmission line 80b is inputted, the directional coupler 83a outputs a part of the signal to the transmission line 80a, and also outputs the remaining signal to an input terminal 14a-2 of the mixer 13a via the output terminal 84a-2 and the transmission line 31a-2.
When a signal on the path A which flows through the transmission line 80b is inputted, the directional coupler 83b outputs a part of the signal to the transmission line 80c, and also outputs the remaining signal to an input terminal 14b-1 of a mixer 13b via the output terminal 84b-1 and the transmission line 31b-1.
Further, when a signal on the path B which flows through the transmission line 80c is inputted, the directional coupler 83b outputs a part of the signal to the transmission line 80b, and also outputs the remaining signal to an input terminal 14b-2 of the mixer 13b via the output terminal 84b-2 and the transmission line 31b-2.
When a signal on the path A which flows through the transmission line 80c is inputted, the directional coupler 83c outputs a part of the signal to the transmission line 80d, and also outputs the remaining signal to an input terminal 14c-1 of a mixer 13c via the output terminal 84c-1 and the transmission line 31c-1.
Further, when a signal on the path B which flows through the transmission line 80d is inputted, the directional coupler 83c outputs a part of the signal to the transmission line 80c, and also outputs the remaining signal to an input terminal 14c-2 of the mixer 13c via the output terminal 84c-2 and the transmission line 31c-2.
Because the signal on the path A which is outputted from the directional coupler 83c to the transmission line 80d is outputted to the terminator 5 via the circulator 82a, the signal is terminated by the terminator 5.
Further, because the signal on the path B which is outputted from the directional coupler 83a to the transmission line 80a is outputted to the terminator 9 via the circulator 81a, the signal is terminated by the terminator 9.
The phases of the signals appearing at the output terminals 84a-1, 84b-1, 84c-1, 84a-2, 84b-2, and 84c-2 of the directional couplers 83a, 83b, and 83c are shown by the following equation (14), and all of the phases of these signals differ from one another.
Output terminal 84a-1:ωt+θ1
Output terminal 84b-1:ωt+θ1+θ2
Output terminal 84c-1:ωtθ1+θ2+θ3
Output terminal 84a-2:ωt+θ4+θ3+θ2
Output terminal 84b-2:ωt+θ4+θ3
Output terminal 84c-2:ωt+θ4 (14)
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
In consideration of the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, the phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (15).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ4+θ3+θ2+θ8)=2 ωt+θ1+θ2+θ3+θ4+θ5+θ8
Output terminal 16b: (ωt+θ1+θ2+θ6)+(ωt+θ4+θ3+θ9)=2 ωt+θ1+θ2+θ3+θ4+θ6+θ9
Output terminal 16c: (ωt+θ1+θ2+θ3+θ7)+(ωt+θ4+θ10)=2 ωt+θ1+θ2+θ3+θ4+θ7+θ10 (15)
In Embodiment 8, because θ5+θ8=θ6+θ9=θ7+θ10=α, all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are shown by the following equation (16), and equal.
2ωt+θ1+θ2+θ3+θ4+α (16)
In above-mentioned Embodiments 1 to 5, the in-phase corporate-feed circuit needs to include the two transmission lines 4 and 8 which are physically different, and it is necessary to connect between the circuit elements 17 by using equal-length transmission lines. Therefore, when a variation occurs between the electric lengths of the transmission lines each connecting between circuit elements 17, there is a case in which the phases of the signals appearing at the output terminals 16a to 16c are not equal.
In contrast with this, in Embodiment 8, because the electric lengths of the transmission lines 80b and 80c each connecting between circuit elements 17 are certainly equal regardless of the directions of the paths A and B, there is provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines.
Further, because the configuration in Embodiment 8 can use the single transmission line 80, there is provided an advantage of being able to reduce the number of transmission lines.
By connecting the output terminals 84a-1 to 84c-1 and 84a-2 to 84c-2 of the directional couplers 83a to 83c directly to the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c, thereby removing the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, there is also provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2.
In Embodiment 8, because the layout requirement imposed on the in-phase corporate-feed circuit is eased, like in the case of above-mentioned Embodiments 1 to 7, the plural circuit elements 17 can be arranged in a straight line, as shown in
Although in above-mentioned Embodiment 8 the example in which the directional couplers 83a, 83b, and 83c are inserted at points of the transmission line 80 is shown, circulators can be alternatively inserted at points of the transmission line 80.
A circulator 85a outputs a signal on a path A which is outputted from a power divider 3 to an output terminal 86a-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14a-1 of a mixer 13a and returns to the output terminal 86a-1 to a transmission line 80b as a signal on the path A.
Further, the circulator 85a outputs a signal on a path B which is outputted from a circulator 85b to an output terminal 86a-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14a-2 of the mixer 13a and returns to the output terminal 86a-2 to a transmission line 80a as a signal on the path B.
The circulator 85b outputs the signal on the path A which is outputted from the circulator 85a to an output terminal 86b-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14b-1 of a mixer 13b and returns to the output terminal 86b-1 to a transmission line 80c as a signal on the path A.
Further, the circulator 85b outputs a signal on the path B which is outputted from a circulator 85c to an output terminal 86b-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14b-2 of the mixer 13b and returns to the output terminal 86b-2 to the transmission line 80b as a signal on the path B.
The circulator 85c outputs the signal on the path A which is outputted from the circulator 85b to an output terminal 86c-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14c-1 of a mixer 13c and returns to the output terminal 86c-1 to a transmission line 80d as a signal on the path A.
Further, the circulator 85c outputs a signal on the path B which is outputted from the power divider 3 to an output terminal 86c-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14c-2 of the mixer 13c and returns to the output terminal 86c-2 to the transmission line 80c as a signal on the path B.
The circulators 85a, 85b, and 85c construct branch circuits.
In the case of having four terminals 87a to 87d, as shown in
Further, a signal inputted from the terminal 87c is outputted from the terminal 87d, and a signal inputted from the terminal 87d is outputted from the terminal 87a.
Therefore, in the case in which the circulator 85a is configured as shown in
Further, in the case in which the circulator 85b is configured as shown in
Further, in the case in which the circulator 85c is configured as shown in
Although, as illustrated in
Each of the circulators 85a, 85b, and 85c can be alternatively comprised of two circulators 88a and 88b each having three terminals as shown in
In this case, a signal inputted from the terminal 87a of the circulator 88a is outputted from the terminal 87b, and a signal inputted from the terminal 87b is outputted from the terminal 89a. A signal outputted from the terminal 89a of the circulator 88a is inputted from the terminal 89b of the circulator 88b. A signal inputted from the terminal 89b of the circulator 88a is outputted from the terminal 87c.
Further, a signal inputted from the terminal 87c of the circulator 88b is outputted from the terminal 87d, and a signal inputted from the terminal 87d is outputted from the terminal 89b. A signal outputted from the terminal 89b of the circulator 88b is inputted from the terminal 89a of the circulator 88a. A signal inputted from the terminal 89a of the circulator 88a is outputted from the terminal 87a.
Next, operations will be explained.
In Embodiment 9, it is assumed that the electric lengths of transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2 are as follows, like in the case of above-mentioned Embodiment 5.
The electric length of the transmission line 31a-1 at an angular frequency ω=θ5
The electric length of the transmission line 31b-1 at the angular frequency ω=θ6
The electric length of the transmission line 31c-1 at the angular frequency ω=θ7
The electric length of the transmission line 31a-2 at the angular frequency ω=θ5
The electric length of the transmission line 31b-2 at the angular frequency ω=θ6
The electric length of the transmission line 31c-2 at the angular frequency ω=θ7
Thus, there is a relationship in which the electric lengths of the transmission lines 31a-1 and 31a-2 are θ5 and equal, the electric lengths of the transmission lines 31b-1 and 31b-2 are θ6 and equal, and the electric lengths of the transmission lines 31c-1 and 31c-2 are θ7 and equal.
When a signal generator 2 generates a signal, the power divider 3 of a signal generating circuit 1 divides the power of the signal into two parts and outputs signals in phase to the circulator 81a and the circulator 82a.
When receiving the signal from the power divider 3, the circulator 81a outputs the signal to an end of the transmission line 80a. As a result, the signal outputted from the power divider 3 is transmitted via the transmission line 80 as a signal on the path A.
When receiving the signal from the power divider 3, the circulator 82a outputs the signal to another end of the transmission line 80d. As a result, the signal outputted from the power divider 3 is transmitted via the transmission line 80 as a signal on the path B.
When receiving the signal on the path A which is outputted from the power divider 3, the circulator 85a outputs the signal to the output terminal 86a-1.
At this time, because the input impedance of the mixer 13a is high, the signal outputted from the output terminal 86a-1 of the circulator 85a and inputted to the input terminal 14a-1 of the mixer 13a is reflected.
As a result, the signal reflected by the mixer 13a returns to the output terminal 86a-1 of the circulator 85a.
The circulator 85a outputs the signal which returns to the output terminal 86a-1 to the transmission line 80b as a signal on the path A.
Further, when receiving the signal on the path B which is outputted from the circulator 85b, the circulator 85a outputs the signal to the output terminal 86a-2.
At this time, because the input impedance of the mixer 13a is high, the signal outputted from the output terminal 86a-2 of the circulator 85a and inputted to the input terminal 14a-2 of the mixer 13a is reflected.
As a result, the signal reflected by the mixer 13a returns to the output terminal 86a-2 of the circulator 85a.
The circulator 85a outputs the signal which returns to the output terminal 86a-2 to the transmission line 80a as a signal on the path B. The signal on the path B which is outputted to the transmission line 80a is outputted to a terminator 9 by the circulator 81a, and is terminated by the terminator 9.
When receiving the signal on the path A which is outputted from the circulator 85a, the circulator 85b outputs the signal to the output terminal 86b-1.
At this time, because the input impedance of the mixer 13b is high, the signal outputted from the output terminal 86b-1 of the circulator 85b and inputted to the input terminal 14b-1 of the mixer 13b is reflected.
As a result, the signal reflected by the mixer 13b returns to the output terminal 86b-1 of the circulator 85b.
The circulator 85b outputs the signal which returns to the output terminal 86b-1 to the transmission line 80c as a signal on the path A.
Further, when receiving the signal on the path B which is outputted from the circulator 85c, the circulator 85b outputs the signal to the output terminal 86b-2.
At this time, because the input impedance of the mixer 13b is high, the signal outputted from the output terminal 86b-2 of the circulator 85b and inputted to the input terminal 14b-2 of the mixer 13b is reflected.
As a result, the signal reflected by the mixer 13b returns to the output terminal 86b-2 of the circulator 85b.
The circulator 85b outputs the signal which returns to the output terminal 86b-2 to the transmission line 80b as a signal on the path B.
When receiving the signal on the path A which is outputted from the circulator 85b, the circulator 85c outputs the signal to the output terminal 86c-1.
At this time, because the input impedance of the mixer 13c is high, the signal outputted from the output terminal 86c-1 of the circulator 85c and inputted to the input terminal 14c-1 of the mixer 13c is reflected.
As a result, the signal reflected by the mixer 13c returns to the output terminal 86c-1 of the circulator 85c.
The circulator 85c outputs the signal which returns to the output terminal 86c-1 to the transmission line 80d as a signal on the path A. The signal on the path A which is outputted to the transmission line 80d is outputted to a terminator 5 by the circulator 82a, and is terminated by the terminator 5.
Further, when receiving the signal on the path B which is outputted from the power divider 3, the circulator 85c outputs the signal to the output terminal 86c-2.
At this time, because the input impedance of the mixer 13c is high, the signal outputted from the output terminal 86c-2 of the circulator 85c and inputted to the input terminal 14c-2 of the mixer 13c is reflected.
As a result, the signal reflected by the mixer 13c returns to the output terminal 86c-2 of the circulator 85c.
The circulator 85c outputs the signal which returns to the output terminal 86c-2 to the transmission line 80c as a signal on the path B.
The phases of the signals appearing at the output terminals 86a-1, 86b-1, 86c-1, 86a-2, 86b-2, and 86c-2 of the circulators 85a, 85b, and 85c are shown by the following equation (17), and all of the phases of these signals differ from one another.
Output terminal 86a-1:ωt+θ1
Output terminal 86b-1:ωt+θ1+2×θ5+θ2
Output terminal 86c-1:ωt+θ1+2×θ5+θ2+2×θ6+θ3
Output terminal 86a-2:ωt+θ4+2×θ7+θ3+2×θ6+θ2
Output terminal 86b-2:ωt+θ4+2×θ7+θ3
Output terminal 86c-2:ωt+θ4
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
In consideration of the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, the phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (18).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ4+2×θ7+θ3+2×θ6+θ2+θ5)=2 ωt+θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7)
Output terminal 16b: (ωt+θ1+2×θ5+θ2+θ6)+(ωt+θ4+2×θ7+θ3+θ6)=2 ωt+θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7)
Output terminal 16c: (ωt+θ1+2×θ5+θ2+θ6+θ3′θ7)+(ωt+θ4+θ7)=2 ωt+θ1+θ2+θ3+θ4+2×(θ5+θ6+θ7) (18)
As is clear from the equation (18), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
Also in Embodiment 9, because the electric lengths of the transmission lines 80b and 80c each connecting between circuit elements 17 are certainly equal regardless of the directions of the paths A and B, there is provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines, like in the case of above-mentioned Embodiment 8
Further, because the configuration in Embodiment 9 can use the single transmission line 80, there is provided an advantage of being able to reduce the number of transmission lines.
By connecting the output terminals 86a-1 to 86c-1 and 86a-2 to 86c-2 of the circulators 85a to 85c directly to the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c, thereby removing the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, there is also provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2.
Embodiment 10Although in above-mentioned Embodiments 1 to 5 the example in which the in-phase corporate-feed circuit includes the two transmission lines 4 and 8 which are physically different is shown, the in-phase corporate-feed circuit can be configured to include a single transmission line along which signals propagate bidirectionally.
A transmission line 90 consists of, for example, a coaxial cable, a waveguide, a microstrip line formed on a printed circuit board, or the like. The transmission line 90 is one along which signals propagate bidirectionally, and has an end connected to a circulator 91a and another end connected to a terminal 92 opened. As a result, a signal transmitted via the transmission line 90 is reflected by the other end of the transmission line 90.
Directional couplers 93a, 93b, and 93c are inserted at points of the transmission line 90, a path through which a signal flows in a first direction, i.e., a path through which, after being outputted from a signal generator 2, a signal flows from the signal generator toward the circulator 91a→ the directional coupler 93a→ the directional coupler 93b→ the directional coupler 93c→ the terminal 92 is referred to as a forward path A, and a path through which a signal flows in a second direction, i.e., a path through which a signal flows from the terminal 92 toward the directional coupler 93c→ the directional coupler 93b→ the directional coupler 93a→ the circulator 91a is referred to as a return path B.
Hereafter, a transmission line between the circulator 91a and the directional coupler 93a is denoted by 90a, a transmission line between the directional coupler 93a and the directional coupler 93b is denoted by 90b, a transmission line between the directional coupler 93b and the directional coupler 93c is denoted by 90c, and a transmission line between the directional coupler 93c and the terminal 92 is denoted by 90d. Thus, the transmission line 90 includes the transmission lines 90a, 90b, 90c, and 90d. It is desirable that all of the characteristic impedances of the transmission lines 90a, 90b, 90c, and 90d are equal.
Although in
An isolator 91 includes the circulator 91a and a terminator 5, and outputs the signal outputted from the signal generator 2 to an end of the transmission line 90a and also blocks the transmission of a signal outputted from the end of the transmission line 90a.
The circulator 91a outputs the signal outputted from the signal generator 2 to the end of the transmission line 90a, and also outputs the signal outputted from the end of the transmission line 90a to the terminator 5.
The circulator 91a has three terminals 65a, 65b, and 65c, as shown in
The directional coupler 93a outputs a part of the signal on the forward path A which is outputted from the circulator 91a to an output terminal 94a-1 (first terminal), and outputs a part of a signal on the return path B which is outputted from the directional coupler 93b to an output terminal 94a-2 (second terminal).
The directional coupler 93a has four terminals, as shown in
The directional coupler 93b outputs a part of a signal on the forward path A which is outputted from the directional coupler 93a to an output terminal 94b-1 (first terminal), and outputs a part of a signal on the return path B which is outputted from the directional coupler 93c to an output terminal 94b-2 (second terminal).
The directional coupler 93b has four terminals, as shown in
The directional coupler 93c outputs a part of a signal on the forward path A which is outputted from the directional coupler 93b to an output terminal 94c-1 (first terminal), and outputs a part of a signal on the return path B which is reflected by the terminal 92 and returns thereto to an output terminal 94c-2 (second terminal).
The directional coupler 93c has four terminals, as shown in
The directional couplers 93a, 93b, and 93c construct branch circuits.
Although in
Although in
Next, operations will be explained.
In Embodiment 10, it is assumed that the electric lengths of the transmission lines 90a, 90b, 90c, and 90d and the electric lengths of transmission lines 31a-1, 31b-1, 31c-1, 31a-2, 31b-2, and 31c-2 are as follows.
The electric length of the transmission line 90a at an angular frequency ω=θ1
The electric length of the transmission line 90b at the angular frequency ω=θ2
The electric length of the transmission line 90c at the angular frequency ω=θ3
The electric length of the transmission line 90d at the angular frequency ω=θ4
The electric length of the transmission line 31a-1 at the angular frequency ω=θ5
The electric length of the transmission line 31b-1 at the angular frequency ω=θ6
The electric length of the transmission line 31c-1 at the angular frequency ω=θ7
The electric length of the transmission line 31a-2 at the angular frequency ω=θ8
The electric length of the transmission line 31b-2 at the angular frequency ω=θ9
The electric length of the transmission line 31c-2 at the angular frequency ω=θ10
It is further assumed that a relationship shown by the equation (3) is established among the electric lengths θ5, θ6, θ7, θ8, θ9, and θ10 of the transmission lines 31a-1, 31a-2, 31b-1, 31b-2, 31c-1, and 31c-2, like in the case of above-mentioned Embodiment 2.
More specifically, there is a relationship in which the sum (θ5+θ8) of the electric lengths of the transmission lines 31a-1 and 31a-2, the sum (θ6+θ9) of the electric lengths of the transmission lines 31b-1 and 31b-2, and the sum (θ7+θ10) of the electric lengths of the transmission lines 31c-1 and 31c-2 are all α and equal.
The signal generator 2 generates a signal and outputs the signal to the circulator 91a.
When receiving the signal from the signal generator 2, the circulator 91a outputs the signal to the end of the transmission line 90a.
Further, when after being reflected by the terminal 92, a signal on the return path B is outputted from the end of the transmission line 90a, the circulator 91a outputs the signal to the terminator 5.
As a result, the signal outputted from the signal generator 2 flows through the transmission line 90 as a signal on the forward path A, and the signal on the return path B which is outputted from the end of the transmission line 90a is terminated by the terminator 5.
When a signal on the forward path A which flows through the transmission line 90a is inputted, the directional coupler 93a outputs a part of the signal to the transmission line 90b, and also outputs the remaining part of the signal to an input terminal 14a-1 of a mixer 13a via the output terminal 94a-1 and the transmission line 31a-1.
Further, when a signal on the return path B which flows through the transmission line 90b is inputted, the directional coupler 93a outputs a part of the signal to the transmission line 90a, and also outputs the remaining signal to an input terminal 14a-2 of the mixer 13a via the output terminal 94a-2 and the transmission line 31a-2.
When a signal on the forward path A which flows through the transmission line 90b is inputted, the directional coupler 93b outputs a part of the signal to the transmission line 90c, and also outputs the remaining signal to an input terminal 14b-1 of a mixer 13b via the output terminal 94b-1 and the transmission line 31b-1.
Further, when a signal on the return path B which flows through the transmission line 90c is inputted, the directional coupler 93b outputs a part of the signal to the transmission line 90b, and also outputs the remaining signal to an input terminal 14b-2 of the mixer 13b via the output terminal 94b-2 and the transmission line 31b-2.
When a signal on the forward path A which flows through the transmission line 90c is inputted, the directional coupler 93c outputs a part of the signal to the transmission line 90d, and also outputs the remaining signal to an input terminal 14c-1 of a mixer 13c via the output terminal 94c-1 and the transmission line 31c-1.
Further, when a signal on the return path B which flows through the transmission line 90d is inputted, the directional coupler 93c outputs a part of the signal to the transmission line 90c, and also outputs the remaining signal to an input terminal 14c-2 of the mixer 13c via the output terminal 94c-2 and the transmission line 31c-2.
The phases of the signals appearing at the output terminals 94a-1, 94b-1, 94c-1, 94a-2, 94b-2, and 94c-2 of the directional couplers 93a, 93b, and 93c are shown by the following equation (19), and all of the phases of these signals differ from one another.
Output terminal 94a-1:ωt+θ1
Output terminal 94b-1:ωt+θ1+θ2
Output terminal 94c-1:ωt+θ1+θ2+θ3
Output terminal 94a-2:ωt+θ1+2×θ2+2×θ3+2×θ4
Output terminal 94b-2:ωt+θ1+θ2+2×θ3+2×θ4
Output terminal 94c-2:ωt+θ1+θ2+θ3+2×θ4 (19)
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
In consideration of the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, the phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (20).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ1+2×θ2+2×θ3+2×θ4+θ8)=2×(ωt+θ1+θ2+θ3+θ4)+θ5+θ8
Output terminal 16b: (ωt+θ1+θ2+θ6)+(ωt+θ1+θ2+2×θ3+2×θ4+θ9)=2×(ωt+θ1+θ2+θ3+θ4)+θ6+θ9
Output terminal 16c: (ωt+θ1+θ2+θ3+θ7)+(ωt+θ1+θ2+θ3+2×θ4+θ10)=2×(ωt+θ1+θ2+θ3+θ4)+θ7+θ10 (20)
Also in Embodiment 10, because θ5+θ8=θ6+θ9=θ7+θ10=α, like in the case of above-mentioned Embodiment 8, all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are shown by the following equation (21), and equal.
2×(ωt+θ1+θ2+θ3+θ4)+α (21)
In above-mentioned Embodiments 1 to 5, the in-phase corporate-feed circuit needs to include the two transmission lines 4 and 8 which are physically different, and it is necessary to connect between the circuit elements 17 by using equal-length transmission lines. Therefore, when a variation occurs between the electric lengths of the transmission lines each connecting between circuit elements 17, there is a case in which the phases of the signals appearing at the output terminals 16a to 16c are not equal.
In contrast with this, in Embodiment 10, because the electric lengths of the transmission lines 90b and 90c each connecting between circuit elements 17 are certainly equal regardless of the forward path A and the return path B, there is provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines.
Further, because the configuration in Embodiment 10 can use the single transmission line 90, there is provided an advantage of being able to reduce the number of transmission lines.
By connecting the output terminals 94a-1 to 94c-1 and 94a-2 to 94c-2 of the directional couplers 93a to 93c directly to the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c, thereby removing the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, there is also provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2.
In Embodiment 10, because the layout requirement imposed on the in-phase corporate-feed circuit is eased, like in the case of above-mentioned Embodiments 1 to 9, the plural circuit elements 17 can be arranged in a straight line, as shown in
Although in above-mentioned Embodiment 10 the example in which the directional couplers 93a, 93b, and 93c are inserted at points of the transmission line 90 is shown, circulators can be alternatively inserted at points of the transmission line 90.
A circulator 95a outputs a signal on a forward path A which is outputted from a circulator 91a to an output terminal 96a-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14a-1 of a mixer 13a and returns to the output terminal 96a-1 to a transmission line 90b as a signal on the forward path A.
The circulator 95a also outputs a signal on a return path B which is outputted from a circulator 95b to an output terminal 96a-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14a-2 of the mixer 13a and returns to the output terminal 96a-2 to a transmission line 90a as a signal on the return path B.
In a case in which the circulator 95a has four terminals 87a to 87d, as shown in
The circulator 95b outputs the signal on the forward path A which is outputted from the circulator 95a to an output terminal 96b-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14b-1 of a mixer 13b and returns to the output terminal 96b-1 to a transmission line 90c as a signal on the forward path A.
The circulator 95b also outputs a signal on the return path B which is outputted from a circulator 95c to an output terminal 96b-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14b-2 of the mixer 13b and returns to the output terminal 96b-2 to the transmission line 90b as a signal on the return path B.
In a case in which the circulator 95b has four terminals 87a to 87d, as shown in
The circulator 95c outputs the signal on the forward path A which is outputted from the circulator 95b to an output terminal 96c-1 (first terminal), and, after that, outputs a signal which is reflected by an input terminal 14c-1 of mixer 13c and returns to the output terminal 96c-1 to a transmission line 90d as a signal on the forward path A.
The circulator 95c also outputs a signal on the return path B which is reflected by a terminal 92 and returns thereto to an output terminal 96c-2 (second terminal), and, after that, outputs a signal which is reflected by an input terminal 14c-2 of the mixer 13c and returns to the output terminal 96c-2 to the transmission line 90c as a signal on the return path B.
In a case in which the circulator 95c has four terminals 87a to 87d, as shown in
The circulators 95a, 95b, and 95c construct branch circuits.
Next, operations will be explained.
In Embodiment 11, it is assumed that the electric lengths of the transmission lines 90a, 90b, 90c, and 90d and the electric lengths of transmission lines 31a-1, 31a-2, 31b-1, 31b-2, 31c-1, and 31c-2 are the same as those shown in above-mentioned Embodiment 9.
A signal generator 2 generates a signal and outputs the signal to the circulator 91a.
When receiving the signal from the signal generator 2, the circulator 91a outputs the signal to an end of the transmission line 90a.
Further, when after being reflected by terminal 92, a signal on the return path B is outputted from the end of the transmission line 90a, the circulator 91a outputs the signal to a terminator 5.
As a result, the signal outputted from the signal generator 2 flows through the transmission line 90 as a signal on the forward path A, and the signal on the return path B which is outputted from the end of the transmission line 90a is terminated by the terminator 5.
When receiving the signal on the forward path A which is outputted from the circulator 91a, the circulator 95a outputs the signal to the output terminal 96a-1.
At this time, because the input impedance of the mixer 13a is high, the signal outputted from the output terminal 96a-1 of the circulator 95a and inputted to the input terminal 14a-1 of the mixer 13a is reflected.
As a result, the signal reflected by the mixer 13a returns to the output terminal 96a-1 of the circulator 95a.
The circulator 95a outputs the signal which returns to the output terminal 96a-1 to the transmission line 90b as a signal on the forward path A.
Further, when receiving the signal on the return path B which is outputted from the circulator 95b, the circulator 95a outputs the signal to the output terminal 96a-2.
At this time, because the input impedance of the mixer 13a is high, the signal outputted from the output terminal 96a-2 of the circulator 95a and inputted to the input terminal 14a-2 of the mixer 13a is reflected.
As a result, the signal reflected by the mixer 13a returns to the output terminal 96a-2 of the circulator 95a.
The circulator 95a outputs the signal which returns to the output terminal 96a-2 to the transmission line 90a as a signal on the return path B. The signal on the return path B outputted to the transmission line 90a is outputted to the terminator 5 by the circulator 91a, and is terminated by the terminator 5.
When receiving the signal on the forward path A which is outputted from the circulator 95a, the circulator 95b outputs the signal to the output terminal 96b-1.
At this time, because the input impedance of the mixer 13b is high, the signal outputted from the output terminal 96b-1 of the circulator 95b and inputted to the input terminal 14b-1 of the mixer 13b is reflected.
As a result, the signal reflected by the mixer 13b returns to the output terminal 96b-1 of the circulator 95b.
The circulator 95b outputs the signal which returns to the output terminal 96b-1 to the transmission line 90c as a signal on the forward path A.
Further, when receiving the signal on the return path B which is outputted from the circulator 95c, the circulator 95b outputs the signal to the output terminal 96b-2.
At this time, because the input impedance of the mixer 13b is high, the signal outputted from the output terminal 96b-2 of the circulator 95b and inputted to the input terminal 14b-2 of the mixer 13b is reflected.
As a result, the signal reflected by the mixer 13b returns to the output terminal 96b-2 of the circulator 95b.
The circulator 95b outputs the signal which returns to the output terminal 96b-2 to the transmission line 90b as a signal on the return path B.
When receiving the signal on the forward path A which is outputted from the circulator 95b, the circulator 95c outputs the signal to the output terminal 96c-1.
At this time, because the input impedance of the mixer 13c is high, the signal outputted from the output terminal 96c-1 of the circulator 95c and inputted to the input terminal 14c-1 of the mixer 13c is reflected.
As a result, the signal reflected by the mixer 13c returns to the output terminal 96c-1 of the circulator 95c.
The circulator 95c outputs the signal which returns to the output terminal 96c-1 to the transmission line 90d as a signal on the forward path A. The signal on the forward path A which is outputted to the transmission line 90d is reflected by the terminal 92, and the reflected signal is inputted to the circulator 95c as a signal on the return path B.
Further, when receiving the signal on the return path B which is reflected by the terminal 92 and returns thereto, the circulator 95c outputs the signal to the output terminal 96c-2.
At this time, because the input impedance of the mixer 13c is high, the signal outputted from the output terminal 96c-2 of the circulator 95c and inputted to the input terminal 14c-2 of the mixer 13c is reflected.
As a result, the signal reflected by the mixer 13c returns to the output terminal 96c-2 of the circulator 95c.
The circulator 95c outputs the signal which returns to the output terminal 96c-2 to the transmission line 90c as a signal on the return path B.
The phase of the signals appearing at the output terminals 96a-1, 96b-1, 96c-1, 96a-2, 96b-2, and 96c-2 of the circulators 95a, 95b, and 95c are expressed by the following equation (22), and all of the phase of these signals differ from one another.
Output terminal 96a-1:ωt+θ1
Output terminal 96b-1:ωt+θ1+2×θ5+θ2
Output terminal 96c-1:ωt+θ1+2×θ5+θ2+2×θ6+θ3
Output terminal 96a-2:ωt+θ1+2×θ5+2×θ2+4×θ6+2×θ3+2×θ4+2×θ7
Output terminal 96b-2:ωt+θ1+2×θ5+θ2+2×θ6+2×θ3+2×θ4+2×θ7
Output terminal 96c-2:ωt+θ1+2×θ5+θ2+2×θ6+θ3+2×θ4 (22)
Each of the mixers 13a to 13c mixes two signals inputted thereto and outputs a mixed signal to a corresponding one of filters 15a to 15c, like that according to above-mentioned Embodiment 1.
When receiving the mixed signal from a corresponding one of the mixers 13a to 13c, each of the filters 15a to 15c prevents the passage of a component having a phase which is the difference between the phases of the two signals and higher-order mixed wave components, which are included in the mixed signal, and passes only a component having a phase which is the sum of the phases of the two signals, which is included in the mixed signal, like that according to above-mentioned Embodiment 1. As a result, the components passing through the filters 15a to 15c and each having a phase which is the sum of the phases of the two signals are outputted from output terminals 16a to 16c.
In consideration of the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, the phases of the signals appearing at the output terminals 16a to 16c of circuit elements 17a to 17c are shown by the following equation (23).
Output terminal 16a: (ωt+θ1+θ5)+(ωt+θ1+2×θ5+2×θ2+4×θ6+2×θ3+2×θ4+2×θ7+θ5)=2×(ωt+θ1+θ2+θ3+θ4+θ5+θ6+θ7)+2×(θ5+θ6)
Output terminal 16b: (ωt+θ1+2×θ5+θ2+θ6)+(ωt+θ1+2×θ5+θ2×θ6+2×θ3+2×θ4+2×θ7+θ6)=2×(ωt+θ1+θ2+θ3+θ4+θ5+θ6+θ7)+2×(θ5+θ6)
Output terminal 16c: (ωt+θ1+2×θ5+θ2+2×θ6+θ3+θ7)+(ωt+θ1+2×θ5+θ2+2×θ6+θ3+2×θ4+θ7)=2×(ωt+θ1+θ2+θ3+θ4+θ5+θ6+θ7)+2×(θ5+θ6) (23)
As is clear from the equation (23), all of the phases of the signals appearing at the output terminals 16a to 16c of the circuit elements 17a to 17c are equal.
Also in Embodiment 11, because the electric lengths of the transmission lines 90b and 90c each connecting between circuit elements 17 are certainly equal regardless of the forward path A and the return path B, there is provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines, like in the case of above-mentioned Embodiment 10.
Further, because the configuration in Embodiment 11 can also use the single transmission line 90, there is provided an advantage of being able to reduce the number of transmission lines.
By connecting the output terminals 96a-1 to 96c-1 and 96a-2 to 96c-2 of the circulators 95a to 95c directly to the input terminals 14a-1 to 14c-1 and 14a-2 to 14c-2 of the mixers 13a to 13c, thereby removing the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2, there is also provided an advantage of eliminating the necessity to take into consideration a variation in the electric lengths of the transmission lines 31a-1 to 31c-1 and 31a-2 to 31c-2.
Embodiment 12In above-mentioned Embodiments 1 to 11, the in-phase corporate-feed circuit that generates plural signals having equal phases from a single signal is shown. The in-phase corporate-feed circuit according to either of above-mentioned Embodiments 1 to 11 can be mounted in an array antenna apparatus.
Further,
In
In the configuration shown in
The frequency of the signal outputted from the PLL 111 can be varied depending on the value of a control signal separately inputted from outside.
A phase shifter 112 adjusts the phase of the signal outputted from the PLL 111. A phase shift amount by which the phase shifter 112 adjusts the phase can be varied depending on the value of a control signal separately inputted from outside.
An amplifier 113 amplifies the amplitude of the signal whose phase is adjusted by the phase shifter 112 and outputs the signal amplified thereby to an output terminal 101.
The output terminal 101 of the transmitter 100 is connected to an element antenna 103.
Further, terminals 102a and 102b of the transmitter 100 are connected to a transmission line 70 which constructs the forward path A, and terminals 102c and 102d are connected to a transmission line 70 which constructs the return path B.
The electric length of the transmission line 70 which is connected between transmitters 100 having the same configuration and which constructs the forward path A is equal to that of the transmission line 70 which constructs the return path B.
Each element antenna 103 is connected to the output terminal 101 of a transmitter 100, and emits, as an electromagnetic wave, a signal outputted from the output terminal 101 of the transmitter 100 to outside. The array antenna is comprised of the plural element antennas 103.
The plural element antennas 103 which construct the array antenna can be configured independently, like those of a horn antenna, or can be formed in a two dimensional array on a single planar substrate, like, for example, those of a patch antenna.
In the example of the array antenna apparatus shown in
Further, in a case in which transmitters 100 each equipped with a circuit element 17 according to either of above-mentioned Embodiments 8 and 9 are used, the plural transmitters 100 are connected by a single transmission line 80.
In addition, in a case in which transmitters 100 each equipped with a circuit element 17 according to either of above-mentioned Embodiments 10 and 11 are used, the plural transmitters 100 are connected by a single transmission line 90.
Next, operations will be explained.
Because a signal outputted from a signal generator 2 flows through the transmission line 70 which constructs the forward path A, the signal is inputted to one input terminal of a mixer 13 in the circuit element 17 mounted in each of the plural transmitters 100.
Further, because a signal flowing through the transmission line 70 which constructs the forward path A after passing through the plural transmitters 100 flows through the transmission line 70 which constructs the return path B, the signal is inputted to another input terminal of the mixer 13 in the circuit element 17 mounted in each of the plural transmitters 100.
The mixer 13 in the circuit element 17 mounted in each of the plural transmitters 100 operates like those according to above-mentioned Embodiments 1 to 11, and the filter 15 in the circuit element 17 mounted in each of the plural transmitters 100 operates like those according to above-mentioned Embodiments 1 to 11.
Therefore, the frequencies and the phases of the signals outputted from the output terminals 16 of the circuit elements 17 mounted in the plural transmitters 100 are equal.
The PLL 111 mounted in each of the plural transmitters 100 receives, as a reference signal, the signal outputted from the output terminal 16 of the circuit element 17, and outputs a signal having a frequency higher than that of the reference signal and synchronized with the reference signal to the phase shifter 112.
At this time, when the values of control signals separately inputted from outside are equal, the frequencies and the phases of the signals outputted from the PLLs 111 mounted in the plural transmitters 100 are equal.
When receiving the signal from the PLL 111, the phase shifter 112 mounted in each of the plural transmitters 100 adjusts the phase of the signal depending on a control signal separately inputted from outside, and outputs the signal after phase adjustment to the amplifier 113.
When receiving the signal after phase adjustment from the phase shifter 112, the amplifier 113 mounted in each of the plural transmitters 100 amplifies the amplitude of the signal and outputs the signal amplified thereby to the output terminal 101.
As a result, the signal is emitted to space as an electromagnetic wave from the element antenna 103 connected to each of the plural transmitters 100.
By setting the phase shift amount for the signal in the phase shifter 112 mounted in each of the plural transmitters 100 for each transmitter, the directions of the electromagnetic waves emitted from the array antenna can be varied.
Although in Embodiment the example of varying the directions of the electromagnetic waves emitted from the array antenna by controlling the phase shift amount for the signal in the phase shifter 112 mounted in each of the plural transmitters 100 is shown, the directions of the electromagnetic waves emitted from the array antenna can be varied by controlling the phase differences among the plural PLLs 111 by using the control signals provided for the PLLs 111 mounted in the plural transmitters 100, as shown in the following Patent Literature 2. In this case, the phase shifter 112 becomes unnecessary.
[Patent Literature 2] Japanese Patent Application Publication No. 2014-49808.
When all of the phases of the reference signals which are the input signals of the PLLs 111 mounted in the plural transmitters 100 are equal, the directions of the electromagnetic waves emitted from the array antenna can be predicted correctly from the phase shift amounts set to the phase shifters 112.
When the phases of the reference signals inputted to the PLLs 111 are not equal and not known, it is difficult to correctly predict the directions of the electromagnetic waves emitted from the array antenna from the phase shift amounts set to the phase shifters 112.
Because the array antenna apparatus according to Embodiment 12 is equipped with in-phase corporate-feed circuits whose circuit sizes are reduced to be smaller than those of in-phase corporate-feed circuits of tournament type, as explained in above-mentioned Embodiments 1 to 11, the circuit size of the array antenna apparatus is also downsized inevitably.
Within the scope of the invention, an arbitrary combination of two or more of the above-mentioned embodiments can be made, various changes can be made in an arbitrary component according to any one of the above-mentioned embodiments, and an arbitrary component according to any one of the above-mentioned embodiments can be omitted.
INDUSTRIAL APPLICABILITYThe in-phase corporate-feed circuit according to the present invention is suitable for use as in-phase corporate-feed circuit s mounted in an array antenna apparatus for which a large space is hardly ensured.
REFERENCE SIGNS LIST1: signal generating circuit; 2: signal generator; 3: power divider; 4, 4a, 4b, 4c: transmission lines; 5: terminator; 6a, 6b, 6c: T-branch units (first branch circuits); 7a, 7b, 7c: output terminals; 8, 8a, 8b, 8c: transmission lines; 9: terminator; 10a, 10b, 10c: T-branch units (second branch circuits); 11a, 11b, 11c: output terminals; 12a, 12b, 12c: phase adding circuits; 13a, 13b, 13c: mixers; 14a-1, 14a-2, 14b-1, 14b-2, 14c-1, 14c-2: input terminals; 15a, 15b, 15c: filters; 16a, 16b, 16c: output terminals; 17a, 17b, 17c: circuit elements; 18a-1, 18b-1, 18c-1, 18a-2, 18b-2, 18c-2: amplifiers; 21, 22: directional couplers; 22a, 22b, 22c, 22d: terminals; 31a-1, 31a-2, 31b-1, 31b-2, 31c-1, 31c-2: transmission lines; 32a, 32b, 32c: transmission lines; 41: ½ frequency divider; 42: noninverting output terminal; 43: inverting output terminal; 51a-1, 51a-2, 51b-1, 51b-2, 51c-1, 51c-2: attenuators; 52a, 52b, 52c, 53a, 53b, 53c: amplifiers; 61a, 61b, 61c: circulators (first branch circuits); 62a, 62b, 62c: output terminals; 63a, 63b, 63c: circulators (second branch circuits); 64a, 64b, 64c: output terminals; 65a, 65b, 65c: terminals; 70, 70a, 70b, 70c, 70d, 70e, 70f: transmission lines; 80, 80a, 80b, 80c, 80d: transmission lines; 81: isolator (first isolator); 81a: circulator; 82: isolator (second isolator); 82a: circulator; 83a, 83b, 83c: directional couplers (branch circuits); 84a-1, 84b-1, 84c-1: output terminals (first terminals); 84a-2, 84b-2, 84c-2: output terminals (second terminals); 85a, 85b, 85c: circulators (branch circuits); 86a-1, 86b-1, 86c-1: output terminals (first terminals); 86a-2, 86b-2, 86c-2: output terminals (second terminals); 87a, 87b, 87c, 87d, 89a, 89b: terminals; 88a, 88b: circulators; 90, 90a, 90b, 90c, 90d: transmission lines; 91: isolator; 91a: circulator; 92: terminal; 93a, 93b, 93c: directional couplers (branch circuits); 94a-1, 94b-1, 94c-1: output terminals (first terminals); 94a-2, 94b-2, 94c-2: output terminals (second terminals); 95a, 95b, 95c: circulators (branch circuits); 96a-1, 96b-1, 96c-1: output terminals (first terminals); 96a-2, 96b-2, 96c-2: output terminals (second terminals); 100: transmitter; 101: output terminal; 102a, 102b, 102c, 102d: terminals; 103: element antenna; 111: PLL; 112: phase shifter; and 113: amplifier.
Claims
1. An in-phase corporate-feed circuit comprising:
- a signal generating circuit configured to divide a signal generated thereby;
- a first transmission line having an end connected to the signal generating circuit, and another end terminated;
- a second transmission line having an end connected to the signal generating circuit, and another end terminated;
- N first branch circuits where N is an integer equal to or greater than 2, each first branch circuit being configured to take, from the first transmission line, a part of one of signals obtained by the division in the signal generating circuit;
- N second branch circuits, each second branch circuit being configured to take, from the second transmission line, a part of another one of the signals obtained by the division in the signal generating circuit; and
- N phase adding circuits, each phase adding circuit being configured to add a phase of a signal taken by one of the N first branch circuits which is n-th when counted from the end of the first transmission line where n is a positive integer equal to or less than N, and a phase of a signal taken by one of the N second branch circuits which is n-th when counted from the other end of the second transmission line, wherein
- an electric length of the first transmission line between one of the first branch circuits which is m-th when counted from the end of the first transmission line where m is a positive integer equal to or less than N−1, and another one of the first branch circuits which is (m+1)-th when counted from the end of the first transmission line, is equal to an electric length of the second transmission line between one of the second branch circuits which is m-th when counted from the other end of the second transmission line, and another one of the second branch circuits which is (m+1)-th when counted from the other end of the second transmission line.
2. The in-phase corporate-feed circuit according to claim 1, wherein each of the first and second branch circuits includes a T-branch unit, a directional, coupler, or a circulator configured to branch the first or the second transmission line.
3. The in-phase corporate-feed circuit according to claim 1, wherein each of the phase adding circuits includes: a mixer configured to mix the signal taken by the one of the N first branch circuits which is n-th when counted from the end of the first transmission line, and the signal taken by the one of the N second branch circuits which is n-th when counted from the other end of the second transmission line, to output a mixed signal; and a filter configured to pass a component having a phase which is a sum of phases of the two signals included in the mixed signal outputted from the mixer.
4. An array antenna apparatus comprising:
- the in-phase corporate-feed circuit according to claim 1, configured to generate plural signals having equal phases from a single signal; and
- an array antenna configured to transmit the plural signals generated by the in-phase corporate-feed circuit.
5. An in-phase corporate-feed circuit comprising:
- a signal generator configured to generate a signal;
- a transmission line comprised of a forward path and a return path, a start point of the forward path being connected to the signal generator and an end point of the return path being terminated;
- N first branch circuits where N is an integer equal to or greater than 2, each first branch circuit being configured to take, from the forward path of the transmission line, a part of the signal generated by the signal generator;
- N second branch circuits, each second branch circuit being configured to take, from the return path of the transmission line, a part of the signal generated by the signal generator; and
- N phase adding circuits each configured to add a phase of a signal taken by one of the N first branch circuits which is n-th when counted from the start point of the forward path where n is a positive integer equal to or less than N, and a phase of a signal taken by one of the N second branch circuits which is n-th when counted from the end point of the return path, wherein
- an electric length of a first transmission line between one of the first branch circuits which is m-th when counted from the start point of the forward path where m is a positive integer equal to or less than N−1, and another one of the first branch circuits which is (m+1)-th when counted from the start point of the forward path, is equal to an electric length of a second transmission line between one of the second branch circuits which is m-th when counted from the end point of the return path, and another one of the second branch circuits which is (m+1)-th when counted from the end point of the return path.
6. The in-phase corporate-feed circuit according to claim 5, wherein each of the first and second branch circuits includes a T-branch unit, a directional coupler, or a circulator configured to branch the first or the second transmission line.
7. The in-phase corporate-feed circuit according to claim 5, wherein each of the phase adding circuits includes: a mixer configured to mix the signal taken by the one of the N first branch circuits which is n-th when counted from the start point of the forward path, and the signal taken by the one of the N second branch circuits which is n-th when counted from the end point of the return path, to output a mixed signal; and a filter configured to pass a component having a phase which is a sum of phases of the two signals included in the mixed signal outputted from the mixer.
8. An array antenna apparatus comprising:
- the in-phase corporate-feed circuit according to claim 5, configured to generate plural signals having equal phases from a single signal; and
- an array antenna configured to transmit the plural signals generated by the in-phase corporate-feed circuit.
9. An in-phase corporate-feed circuit comprising:
- a transmission line along which signals propagate bidirectionally;
- a signal generator configured to generate a signal to be outputted to the transmission line;
- N branch circuits where N is an integer equal to or greater than 2, each branch circuit being configured to output a signal flowing through the transmission line in a first direction to a first terminal, and to output a signal flowing through the transmission line in a second direction to a second terminal, and
- N phase adding circuits, each phase adding circuit having two input terminals connected to the first and second terminals, and configured to add a phase of the signal which is outputted by a corresponding one of the branch circuits from the first terminal, and a phase of the signal which is outputted by the corresponding, one of the branch circuits from the second terminal.
10. The in-phase corporate-feed circuit according to claim 9, further comprising:
- a power divider configured to divide the signal generated by the signal generator;
- a first isolator configured to output one of signals obtained by the division in the power divider to an end of the transmission line, and to block transmission of a signal outputted from the end of the transmission line; and
- a second isolator configured to output another one of the signals obtained by the division in the power divider to another end of the transmission line, and to block transmission of a signal outputted from the other end of the transmission line, wherein
- each of the N branch circuits outputs a signal flowing through the transmission line from the first isolator toward the second isolator to the first terminal, and outputs a signal flowing through the transmission line from the second isolator toward the first isolator to the second terminal.
11. The in-phase corporate-feed circuit according to claim 10, wherein each of the branch circuits includes a directional coupler configured to output a part of a signal flowing through the transmission line from the first isolator toward the second isolator to the first terminal, and to output a part of a signal flowing through the transmission line from the second isolator toward the first isolator to the second terminal.
12. The in-phase corporate-feed circuit according to claim 10, wherein each of the branch circuits includes a circulator configured to output a signal flowing through the transmission line from the first isolator toward the second isolator to the first terminal, and, thereafter, output, as a signal flowing from the first isolator toward the second isolator, a signal inputted from the first terminal to the transmission line, and configured to output a signal flowing through the transmission line from the second isolator toward the first isolator to the second terminal, and thereafter, output, as a signal flowing from the second isolator toward the first isolator, a signal inputted from the second terminal to the transmission line.
13. The in-phase corporate-feed circuit according to claim 9, further comprising an isolator configured to output the signal generated by the signal generator to an end of the transmission line, and to block transmission of a signal outputted from the end of the transmission line, wherein
- each of the N branch circuits outputs a signal flowing through the transmission line from the isolator toward another end of the transmission line to the first terminal, and outputs a signal flowing, from the other end toward the isolator to the second terminal by reflection at the other end of the transmission line.
14. The in-phase corporate-feed circuit according to claim 13, wherein each of the branch circuits includes a directional coupler configured to output a part of a signal flowing through the transmission line from the isolator toward the other end of the transmission line to the first terminal, and to output a part of a signal flowing from the other end toward the isolator to the second terminal by reflection at the other end of the transmission line.
15. The in-phase corporate-feed circuit according to claim 13, wherein each of the branch circuits includes a circulator configured to:
- output a signal flowing through the transmission line from the isolator toward the other end of the transmission line to the first terminal,
- thereafter output, as a signal flowing from the isolator toward the other end, a signal inputted from the first terminal to the transmission line,
- output a signal flowing from the other end toward the isolator to the second terminal by reflection the signal generated by the signal generator at the other end of the transmission line, and,
- thereafter output, as a signal flowing from the other end toward the isolator, a signal inputted from the second terminal to the transmission line.
16. The in-phase corporate-feed circuit according to claim 13, wherein the other end of the transmission line is opened, or a load configured to reflect the signal generated by the signal generator is connected to the other end of the transmission line.
17. The in-phase corporate-feed circuit according to claim 9, wherein each of the phase adding circuits includes:
- a mixer having two input terminals connected to the first and second terminals, configured to mix a signal which is outputted by a corresponding one of the branch circuits from the first terminal and a signal which is outputted by the corresponding one of the branch circuits from the second terminal, to output a mixed signal; and
- a filter configured to pass a component having a phase which is a sum of phases of the two signals included in the mixed signal outputted from the mixer.
18. An array antenna apparatus comprising: an array antenna configured to transmit the plural signals generated by the in-phase corporate-feed circuit.
- the in-phase corporate-feed circuit according to claim 9, configured to generate plural signals having equal phases from a single signal; and
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Type: Grant
Filed: Feb 2, 2016
Date of Patent: Aug 18, 2020
Patent Publication Number: 20180309179
Assignee: MITSUBISHI ELECTRIC CORPORATION (Tokyo)
Inventors: Hiroyuki Mizutani (Tokyo), Kenichi Tajima (Tokyo), Morishige Hieda (Tokyo)
Primary Examiner: Robert J Pascal
Assistant Examiner: Kimberly E Glenn
Application Number: 15/771,188
International Classification: H01P 1/18 (20060101); H01P 5/12 (20060101); H01Q 21/00 (20060101); H01Q 3/30 (20060101); H01P 1/213 (20060101); H01Q 21/22 (20060101); H01P 1/24 (20060101); H01P 1/36 (20060101); H01P 1/38 (20060101); H01P 5/18 (20060101);
